用一元二次方程的解法,解一下这道题吧
1个回答
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(2X+29)(2X+22)=29×22+29×22×1/4
4X²+44X+58X+638=638+159.5
4X²+102X=159.5
X²+25.5X=39.875
X²+25.5X+12.75²=39.875+12.75²
(X+12.75)²=202.4375
X+12.75=±√202.4375
X+12.75=√202.4375或X+12.75=-√202.4375(不合题意,舍去)
所以X+12.75=√202.4375
X=√202.4375-12.75≈1.5
答:镜框边的宽度大约是1.5厘米
4X²+44X+58X+638=638+159.5
4X²+102X=159.5
X²+25.5X=39.875
X²+25.5X+12.75²=39.875+12.75²
(X+12.75)²=202.4375
X+12.75=±√202.4375
X+12.75=√202.4375或X+12.75=-√202.4375(不合题意,舍去)
所以X+12.75=√202.4375
X=√202.4375-12.75≈1.5
答:镜框边的宽度大约是1.5厘米
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