Question

3x+4y=43 find the value of y when x equals 9

Answer 1

4=y or y=4 because substitute x which is 9 and do the inverse all operation until y is left.

Answer 2

To start take the equation and then plug in 9 for x
3x+4y=43
3(9)+4y=43
27+4y=43
Subtract 27 from each side to get all of the y's by themselves
27+4y-27=43-27
4y=16
Divide by four to get the value of one y
4y/4=16/4
y=4