Question 681972
4x²-32x+164=0
4x²-32x=-164
4(x²-8x)=-164
x²-8x=-41    （-8/2）²=16
x²-8x+16=-41+16    completing the square
（x-4)(x-4)=-25
(x-4)²=-25        factored form
x=+√25+4 x=+5+4 x=9
x=-√25+4 x=-5+4 x=-1      （√25=5）

so x=9，-1