Question

if y is proportional to 2x-7,and y=-9 when x=2,find x when y=-15.Please show me step by step

Answer 1

proportional which means...

y = k(2x-7)
-9 = k(2(2) - 7)
-9 = k(4 - 7)
-9 = k(-3)
-9 = -3k
divide both sides by -3....

3 = k
when y = -15...

-15 = (3)(2x-7)
-15 = 6x - 21
21 - 15 = 6x
6 = 6x

divide both sides by 6...

1 = x

Answer 2

k is the proportionality constant

Answer 3

Thank you so much