2a2b+5ab−4

Question

if a=-4
and b=5

Answer 1

Substitute the values of a and b into the expression:

2(5)(-4) + 5(-4)(5) - 4

Simplify:

2(-20) + 5(-20) - 4
= -40 - 100 - 4
= -144

Therefore, when a = -4 and b = 5, the expression 2a^2 + 5ab - 4 equals -144.