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The answer depends on the form of the equation and the domain.

For example,

  • there is no solution for x + 2 = 0 if the domain is positive integers, but there is if x can be a negative integer.
  • there is no solution for 2x = 1 for integer x but there is if x can be a rational number.
  • there is no solution for x^2 = 2 for rational x but there is if x can be an irrational number.
  • there is no real solution for x^2 = -2 for real x there is if x can be a complex number.

There are many other equations in one variable for which cannot be solved.

However, for simple equations, you may get a solution by making the same changes to both sides of the equation (with some exceptions, like division by zero, or taking square roots, etc) until you rename one side as the variable.

For example, to solve

(2x + 3)/5 = 9

Multiply both sides by 5: 2x + 3 = 45

Subtract 3 from both sides: 2x = 42

Divide both sides by 2: x = 21.

Solution of inequalities is the same except that if you multiply or divide by a negative number then the inequality changes direction.

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Q: How can you solve an equation or inequality in one variable?
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Can you solve for a variable in an expression or equation?

you can only solve for one in an equation so it can equal something


Can you solve a variable with an equation?

When an equation has a variable in it (only one), then there are only certainvalues the variable can have that will make the equation a true statement."Solving" the equation means finding those values for the variable.


What is 2x -2?

4


How do you use different techniques to solve linear equations?

1. Elimination: Select two equations and a variable to eliminate. Multiply each equation by the coefficient if that variable in the other equation. If the signs of the coefficient for that variable in the resulting equations are the same then subtract one new equation from the other. If they have opposite signs then add them. You will now have an equation without that variable. Repeat will other pairs and you will end up with one fewer equation and one fewer variable. Repeat this process: after each round you will have one fewer equation and one fewer variable. Keep going until you are left with one equation in one variable. Solve that. Then work backwards solving for the other variables.2. Substitution: Select a equation and a variable. Make that variable the subject of the equation. The right hand side of this equation is an expression for that variable. Substitute this expression for the variable is each of the other equations. Again, one fewer equation in one fewer variable. Continue until you are left with one equation in one variable. Solve that. Then work backwards solving for the other variables.3. Matrix inversion: If A is the nxn matrix of coefficients, X is the nx1 [column] matrix of variables and B is the nx1 matrix of the equation constants, then X = A^-1*B where A^-1 is the inverse of matrix A.


When using the substitution to solve nonlinear system of equations you should first see if you can one variable if you can one variable in one of the equation in the system?

The general idea is to solve one of the equations for one variable - in terms of the other variable or variables. Then you can substitute the entire expression into another equation or other equations; as a result, if it works you should end up having one less equation, with one less variable.

Related questions

What must be done get a variable alone on one side of an equation or inequality in order to solve the equation or inequality the answeranswer has eighteen letters with s being the second?

isolate the variable


What is it called when a when you get a variable alone on one side of an equation or inequality in order to solve the equation or inequality?

each of the four regions created on the coordinate plane by the x- and y-axes.


Can you solve for a variable in an expression or equation?

you can only solve for one in an equation so it can equal something


Can you solve a variable with an equation?

When an equation has a variable in it (only one), then there are only certainvalues the variable can have that will make the equation a true statement."Solving" the equation means finding those values for the variable.


What is 2x -2?

4


Solve the inequality 9 h plus 2 minus 79?

This cannot be solved. Just like an equation, an inequality has to have at least one variable and at least one operator, such as less than, greater than, etc. Yours has no operator. Please restate your question.


How does writing equivalent equations help you solve a system of equations?

You can write an equivalent equation from a selected equation in the system of equations to isolate a variable. You can then take that variable and substitute it into the other equations. Then you will have a system of equations with one less equation and one less variable and it will be simpler to solve.


How do you use different techniques to solve linear equations?

1. Elimination: Select two equations and a variable to eliminate. Multiply each equation by the coefficient if that variable in the other equation. If the signs of the coefficient for that variable in the resulting equations are the same then subtract one new equation from the other. If they have opposite signs then add them. You will now have an equation without that variable. Repeat will other pairs and you will end up with one fewer equation and one fewer variable. Repeat this process: after each round you will have one fewer equation and one fewer variable. Keep going until you are left with one equation in one variable. Solve that. Then work backwards solving for the other variables.2. Substitution: Select a equation and a variable. Make that variable the subject of the equation. The right hand side of this equation is an expression for that variable. Substitute this expression for the variable is each of the other equations. Again, one fewer equation in one fewer variable. Continue until you are left with one equation in one variable. Solve that. Then work backwards solving for the other variables.3. Matrix inversion: If A is the nxn matrix of coefficients, X is the nx1 [column] matrix of variables and B is the nx1 matrix of the equation constants, then X = A^-1*B where A^-1 is the inverse of matrix A.


How doI solve system of equations by substitution?

Assuming the simplest case of two equations in two variable: solve one of the equations for one of the variables. Substitute the value found for the variable in all places in which the variable appears in the second equation. Solve the resulting equation. This will give you the value of one of the variables. Finally, replace this value in one of the original equations, and solve, to find the other variable.


When using the substitution to solve nonlinear system of equations you should first see if you can one variable if you can one variable in one of the equation in the system?

The general idea is to solve one of the equations for one variable - in terms of the other variable or variables. Then you can substitute the entire expression into another equation or other equations; as a result, if it works you should end up having one less equation, with one less variable.


How do you solve for the indicated variable?

Algebraically manipulate the equation until you have the indicated variable on one side of the equation and all of the other factors on the other side.


What is an equation with one or two variables?

When you solve a one-variable equation, your goal is to isolate the variable.To isolate the variable means to make it be alone on one side of the equals sign.In the equation shown here, you can isolate the variable by subtracting 9 from both sides of the equation and simplifying