Question

What is the value of b2 - 4ac for the following equation?

x(x + 8) = 9

Answer 1

x(x+8)=9
\[x^{2}+8x-9=0\]
a=1
b=8
c=-9

b^2=64
4*a*c=4*1*(-9)
=-36

b^2-4ac=64-(-36)
=64+36
=100