Question

Evaluate the expression 7a² - 3b³ when a) a= 4, b= -2 b) a= -8, b=5

You will end up with 2 answers here, substitute and solve.

Answer 1

Explanation:

7a²-3b²

Replace a=4, b=2

7*4²-3*2²

= 112-12

= 100 first answer

7a²-3b²

Replace a=8, b=5

7*8²-3*5²

448-75

= 373 second answer