Question

Find the possible value or values of r in the quadratic equation r2 -7r-8=0

Answer 1

r^2+r-8r-8=0
r(r+1)-8(r+1)=0
(r+1)(r-8)=0
r+1=0,  r=-1
r-8=0 ,  r=8 

answer: r=-1 or r=8