Question

解方程：(29-2x)(22-2x)=478.5

解方程：
1、(29-2x)(22-2x)=478.5
2、{[5+（5-1.25x）]/2}x=5

Answer 1

、(29-2x)(22-2x)=478.5
638-58x-44x+4x^2=478.5
4x^2-102x+159.5=0
x^2-25.5x+39.875=0
[x-12.75]^2=122.6875
x-12.75=+/-11.08
x1=23.83
x2=1.67

Answer 2

解方程：
1、(29-2x)(22-2x)=478.5
638-58x-44x+4x^2=478.5
4x^2-102x+159.5=0
x^2-25.5x+39.875=0
[x-12.75]^2=122.6875
x-12.75=+/-11.08
x1=23.83
x2=1.67

2、{[5+（5-1.25x）]/2}x=5
[(10-1.25x)/2]x=5
[5-0.625x]x=5
5x-0.625x^2-5=0
x^2-8x+8=0
[x-4]^2=8
x-4=+/-2根2
X1=4+2根2
X2=4-2根2

Answer 3

sqr表示根号
638-58x-44x+4x^2=478.5
4x^2-102x+159.5=0
x=[102+ -sqr(102^2-4*4*159.5)]/8=(102+ -2sqr1963)/8
=(51+ -sqr1963)/4
2.(10-1.25x)x=10
1.25x^2-10x+10=0
x=(10+ -5sqr2)/2.5=4+ -2sqr2