(x+1/2y)(x-1/2y)(x²-1/4y²)(0.3-3y)²-(-3x)y(1/3a-b)(-1/3a-b)-(-b)²(1/2x+1)²+(-1/4x²)一个正方形,如果先把一组对边延长2cm,再把另一组对边减少2cm,这时得到的长
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![(x+1/2y)(x-1/2y)(x²-1/4y²)(0.3-3y)²-(-3x)y(1/3a-b)(-1/3a-b)-(-b)²(1/2x+1)²+(-1/4x²)一个正方形,如果先把一组对边延长2cm,再把另一组对边减少2cm,这时得到的长](/uploads/image/z/2992830-6-0.jpg?t=%EF%BC%88x%2B1%2F2y%EF%BC%89%EF%BC%88x-1%2F2y%EF%BC%89%EF%BC%88x%26%23178%3B-1%2F4y%26%23178%3B%EF%BC%89%EF%BC%880.3-3y%EF%BC%89%26%23178%3B-%EF%BC%88-3x%EF%BC%89y%EF%BC%881%2F3a-b%29%28-1%2F3a-b%EF%BC%89-%EF%BC%88-b%EF%BC%89%26%23178%3B%EF%BC%881%2F2x%2B1%EF%BC%89%26%23178%3B%2B%EF%BC%88-1%2F4x%26%23178%3B%EF%BC%89%E4%B8%80%E4%B8%AA%E6%AD%A3%E6%96%B9%E5%BD%A2%2C%E5%A6%82%E6%9E%9C%E5%85%88%E6%8A%8A%E4%B8%80%E7%BB%84%E5%AF%B9%E8%BE%B9%E5%BB%B6%E9%95%BF2cm%2C%E5%86%8D%E6%8A%8A%E5%8F%A6%E4%B8%80%E7%BB%84%E5%AF%B9%E8%BE%B9%E5%87%8F%E5%B0%912cm%2C%E8%BF%99%E6%97%B6%E5%BE%97%E5%88%B0%E7%9A%84%E9%95%BF)
(x+1/2y)(x-1/2y)(x²-1/4y²)(0.3-3y)²-(-3x)y(1/3a-b)(-1/3a-b)-(-b)²(1/2x+1)²+(-1/4x²)一个正方形,如果先把一组对边延长2cm,再把另一组对边减少2cm,这时得到的长
(x+1/2y)(x-1/2y)(x²-1/4y²)
(0.3-3y)²-(-3x)y
(1/3a-b)(-1/3a-b)-(-b)²
(1/2x+1)²+(-1/4x²)
一个正方形,如果先把一组对边延长2cm,再把另一组对边减少2cm,这时得到的长方形面积恰好与原正方形边长减少1cm后的正方形面积相等,求原正方形面积
(x+1/2y)(x-1/2y)(x²-1/4y²)(0.3-3y)²-(-3x)y(1/3a-b)(-1/3a-b)-(-b)²(1/2x+1)²+(-1/4x²)一个正方形,如果先把一组对边延长2cm,再把另一组对边减少2cm,这时得到的长
(x+1/2y)(x-1/2y)(x²+1/4y²)
=(x²-y²/4)(x²+y²/4)
=x^4-y^4/16;
(0.3-3y)²-(-3x)y
=0.09+9y²-1.8y+3xy;
(1/3a-b)(-1/3a-b)-(-b)²
=b²-a²/9-b²
=-a²/9;
(1/2x+1)²+(-1/4x²)
=x²/4+1+x-x²/4
=x+1;
一个正方形,如果先把一组对边延长2cm,再把另一组对边减少2cm,这时得到的长方形面积恰好与原正方形边长减少1cm后的正方形面积相等,求原正方形面积
设原边长为x厘米,则有:
(x+2)(x-2)=(x-1)²;
x²-4=x²-2x+1;
2x=5;
x=2.5;
原来面积=2.5×2.5=6.25平方厘米