Question

Which is a factor of 2x2+ 8x − 90?
x + 2
x − 15
x + 9
x − 4

Answer 1

mm.. may be x+9

Answer 2

\(\large 2x^2+8x-90\)\(\large =2(x^2+4x-45)\\\large =2(x^2+9x-5x-45)\\\large =2[x(x+9)-5(x+9)]\\\large =2(x-5)(x+9)\)

Thus, \(\large x + 9\) is a factor