What does it mean to solve an equation

Step-by-step explanation: Solving an equation means finding the value of the variable that makes the equation true.

Let's look at an example.

Solve the following equation.

3x + 1 = 7

To solve the equation, we need to get x by itself on one side and we do that by subtracting 1 from both sides to get 3x = 6. Now just divide both sides of the equation by 2 and we find that x = +2.

Thus, the solution to the equation is x = +2.

So the value of the variable is +2.

second option

step-by-step explanation:

the measures of a triangle equal 180. use that to find x.

2x+3x+4x=180

9x=180

9x/9=180/9

x=20

now you know x, you know angle a is 40°, angle b is 60°, angle c is 80°.

because angle a is 40°, the first option doesn't work.

because angle b is 60°, the second option does work.

when you add angle a and b, you get 100°. complementary means it equals 90°, so the third option doesn't work.

when you add angle a and c, you get 120°, which is not 100.