sangers1959

Verified answer

2.
y=x^2-8x+7
y`=2x-8=0
2x=8
x=4
y(4)=4^2-8*4+7=16-32+7=-9=ymin.
4.
y=x^2/4     y=5x-16
x^2/4=5x-16
x^2=20x-64
x^2-20x+64=0   D=144
x=16   y=16^2/4=64   (16;64)
x=4     y=4^2/4=4        (4;4).