No.
Linear Equations are equations with variable with power 1 for eg: 5x + 7 = 0 Simultaneous Equations are two equations with more than one variable so that solving them simultaneously
Simultaneous equation* * * * *No, simultaneous equations are two or more equations that have all to be true at the same time (simultaneously) for the solution.An equation with more than one variable is a multivariate equaion.Area = 0.5*Length*Height or a = 0.5*l*h for the area of a triangle has more than one variables, but it is certainly not simultaneous.An equation with a variable is called a single variable equation. An equation that has more than one variable is called as a multi-variable equation. A polynomial equation has one variable in different powers: a common example is quadratic equations.
A system of equations is a set of equations with more than one variable dealing with the same material. If there are 2 variables, then the system must have 2 equations before it can be solved. 3 variables need 3 equations, etc.
Select one equation from a system of linear equations. Select a second equation. Cross-multiply the equations by the coefficient of one of the variables and subtract one equation from the other. The resulting equation will have one fewer variable. Select another "second" equation and repeat the process for the same variable until you have gone through all the remaining equations. At the end of the process you will have one fewer equation in one fewer variable. That variable will have been eliminated from the system of equations. Repeat the whole process again with another variable, and then another until you are left with one equation in one variable. That, then, is the value of that variable. Substitute this value in one of the equations from the previous stage to find the value of a last variable to be eliminated. Work backwards to the first variable. Done! Unless: when you are down to one equation it is in more than one variable. In this case your system of equations does not have a unique solution. If there are n variables in your last equation then n-1 are free to take any value. These do not have to be from those in the last equation. or when you are down to one variable you have more than one equation. If the equations are equivalent (eg 2x = 5 and -4x = -10), you are OK. Otherwise your system of equations has no solution.
Yes, you can have more than one variable
if you change more than one variable, you will not know which one has had an effect on the experiment. If the outcome changes when one variable is altered, then the change can only be due to the one variable, by logical deduction.
Because you can't be sure what about the variable is changing or how it changes. The different factors of the variable can also change the experiment in different ways, therefore making the experiment more complicated.
Yes, an expression can have more than one variable.
Not all rational equations have a single solution but can have more than one because of having polynomials. All rational equations do have solutions that cannot fulfill the answer.
multi-step equations
Elements that can have more than one possible ionic charge are called elements with variable valency. This can occur when an element has multiple oxidation states, leading to the formation of ions with different charges in chemical reactions. Transition metals are common examples of elements with variable valency.