How do you solve an equation with 2 different variables?

Answer 1

Although the answer below would suggest otherwise, it can be proved that a single linear equation in two variable cannot be solved. The whole point of it is that it is a linear equation which represents a line. The coordinates of ANY (repeat ANY) point on the line will satisfy the equation - not just 1, not 3, nor 5 nor 6000 but infinitely many points. Each and every point on the line is a solution.

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Easy, as long as you follow these steps.

Lets say you are given an equation such as

25 = 2x+2y

You have two variables! Oh no! Well, now take this one step at a time, because it's a multiple step equation.

25 = 2x+2y (divide both sides by 2)

25/2 = 12.5

2x/2 = x

2y/2 = y

Now you have 12.5 = x + y

You still have two variables, but now you can work with them a bit better.

Considering this is an equation that would normally just be simplified, you must substitute any number greater than zero, but less than or equal to 12.5, for either x or y.

x = 11.5

Subtract the substitution of x (11.5) from the answer (q) and you will get

1 = y

Now you have both the value of your x and the value of the y.

x = 11.5

y = 1

12.5 = 11.5 + 1

However, you could substitute a number greater than 12.5 such is demonstrated below.

12.5 = x + y

x = 13.5

Now subtract x from your answer (q) and you will get

y = -1

Substitute the values again and you will get

12.5 = 13.5 - 1

Both are true, but you need to go back to the original equation now. You need to multiply both sides by two to get your final answer.

25 = 2x+2y

25 = 2(11.5)+2(1) is your final answer

OR

25 = 2(13.5)+2(-1) could also be your final answer, depending on which you chose.