Answer: third one
Step-by-step explanation:
Answer:
81
Step-by-step explanation:
9 x 9 = 81
So, 81 is the perfect square.
Answer:The particles in a solid are tightly packed and locked in place. Although we cannot see it or feel it, the particles are moving = vibrating in place.
Answer:
21.
Step-by-step explanation:
f(x) = 2x^2 - 3x + 7.
When x = -2,
f(-2) = 2(-2)^2 - 3(-2) + 7
= 2(4) - (-6) + 7
= 8 + 6 + 7
= 21.