A linear equation with two variables is given 4a − 7b + 100 = 0. Using it, write the variable a through another variable b.

To express one variable in terms of another, you need to move one variable to the right and another to the left. Since in this case it is necessary to express the variable a through the variable b, we will transfer a to the left side, b – to the right, and we will transfer all other numerical values ​​to the right side as well.

Important! When transferring a variable or a numerical value from one side to the other, the sign of the variable changes to the opposite.

For this case:

It used to be 7b, but it will become + 7b. It was + 100, will become – 100. We get:

4a = 7b – 100.

It remains only to divide the right side by 4:

a = (7b – 100) / 4.

Answer: a = (7b – 100) / 4.