Answer:
21.4 mm
Step-by-step explanation:
area ÷ base = height
164.78 mm^2 ÷ 7.7 mm
Check:
base • height = area
7.7 mm • 21.4 mm = 164.78 mm^2
average is the answer.
(7x^2-2) - (2x^2 - 5x + 3)
5(x^2+x-1)