y=(4+x)( 10-x)=40-4x+ 10x-x^2=-x^2+6x+40

2) Q=aπ(D/2)^2=aπD^2/2

3)

When m 2-5m+7 = 1, that is, m=2 or 3, this function is linear.

When m 2-5m+7 =1,that is, m=2, this function is a proportional function.

When m 2-5m+7 = 2 and m = (5 √ 5)/2, this function is a quadratic function.

4) When x=2, the minimum value is -4.

When x=0, the maximum value is 0.

5) Because y = ax 2 is symmetrical about y, (x 1, 5) and (x 2, 5) are symmetrical points.

So x 1+x2=0,

So when x=x 1+x2=0, the value of y is 0.