Question

Simplify the expression and then substitute the given number for the variable. For expression 8a2+6b+9a2+9b2+3b, find the value if a=2,b=−1.

Answer 1

Answer: 68

Explanation:

Simplifying the expression:

= 8a² + 6b + 9a² + 9b² + 3b

Collect like terms

= 8a² + 9a² + 6b + 3b + 9b²

= 17a² + 9b + 9b²

We then substitute a=2,b=−1.

= 17a² + 9b + 9b²

= 17(2)² + 9(-1) + 9(-1)²

= 68 -9 + 9

= 68