Question

Given that 7x - 3y = 23

Find when y = -2
Give your answer as an improper fraction in its simplest form.​

Answer 1

7x - 3(-2) = 23
7x - - 6 = 23 (two minuses make a plus)
so it’s gonna be 7x + 6 = 23
Now you have isolate you x, so move everything else to the other side, but remember to change your sign when transferring to the other side

7x = 23 - 6
7x = 17
To isolate x in this multiple, you divide by 7 (because the inverse of multiplication is division)
x = 17/7