第2章 2.11

(1)

x3=2|x-3|=2

(x3)2=4x26x+9=4x26x+5=0(x5)(x1)=0x=1,5(x-3)^2=4 \qquad x^2-6x+9=4 \qquad x^2-6x+5=0 \qquad (x-5)(x-1)=0 \qquad x=1,5

(2)

1x=5|1-x|=5

(1x)2=2512x+x2=25x22x24=0(x6)(x+4)=0x=6,4(1-x)^2=25 \qquad 1-2x+x^2=25 \qquad x^2-2x-24=0 \qquad (x-6)(x+4)=0 \qquad x=6,-4

(3)

2x3=7|2x-3|=7

(2x3)2=494x212x+9=494x212x40=04(x23x10)=4(x5)(x+2)=0(2x-3)^2=49 \qquad 4x^2-12x+9=49 \qquad 4x^2-12x-40=0 \qquad 4(x^2-3x-10)=4(x-5)(x+2)=0

x=5,2x=5,-2

解説: r31bn1z