Answer:
8,9
or
-9,-8
Step-by-step explanation:
x(x + 1) = 72
Distribute
x^2 +x = 72
Subtract 72 from each side
x^2 +x -72 =0
Factor
(x-8) (x+9) =0
Using the zero product property
x-8=0 x+9 =0
x-8+8=0+8 x+9-9=0-9
x=8 or x=-9
1st case: x=8, x+1 =9
2nd case: x=-9, x+1 = -8
