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用因式分解法解方程:(3y-1)²-8(3y-1)+15=0 4(y+1)²-9(y-1)²

来源:学生作业帮 编辑:作业帮 分类:数学作业 时间:2024/05/15 10:45:50
用因式分解法解方程:(3y-1)²-8(3y-1)+15=0 4(y+1)²-9(y-1)²=0
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(3y-1)²-8(3y-1)+15=0
(3y-1)²-8(3y-1)+16-1=0
(3y-1)²-8(3y-1)+4²=1
[(3y-1)-4]²=1
(3y-5)²=1
则有:
3y-5=1
3y-5=-1
解得:
y1=2
y2=4/3

4(y+1)²-9(y-1)²=0
[2(y+1)]²-[3(y-1)]²=0
[2(y+1)+3(y-1)][2(y+1)-3(y-1)]=0
(5y-1)(-y+5)=0
则有:
5y-1=0
-y+5=0
解得:
y1=1/5
y2=5