一楼是机器人回答的,答非所问,完全胡扯.
二楼解答错了,正确解答如下：
【Question 8】
Solution ：
f(x) = 5x + 2,g(x) = x² + 2x
This is a question of composite function.
Sub g(x) into f(x),we get:
f(g(x)) = 5(x² + 2x) + 2 = 5x² + 10x + 2
So,the answer is (d)
【Question 9】
Solution :
y = 2x² + 8x + 3 [1]
Turning point is the staionary point,so
Let dy/dx = 4x + 8 = 0,we obtain x = -2
Sub x = -2 into eq [1],we have y = 8 - 16 + 3 = - 5
So,the turning point is (-2,-5)
The answer is (b).
