# Evaluate the expression $$5a + 2b \times (3a - {b^2})$$ , if a = –1 and b = 2.

-33

Explanation

First substitute the variable values in the expression. Then use order of operations to evaluate the expression. Substituting variable values, $$5 a+2 b \times\left(3 a-b^{2}\right)=5(-1)+2(2) \times\left(3(-1)-2^{2}\right)=-5+4 \times(-3-4)$$ . Performing parentheses first, then the multiplication, and then addition:
-5 + 4 x (-3 - 4) = -5 + 4 x (-7) = -5 – 28 = -33