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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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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?
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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 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.
