> 数学 >
1.(3x-5)平方-(2x+7)平方
2.(x+y+1)(x+x-1)
3.(2x-y-3)平方
4.[(x+2)(x-2)]平方
运用乘法公式计算
人气:251 ℃ 时间:2020-01-29 00:31:57
解答
1.(3x-5)平方-(2x+7)平方
=(9x²-30x+25)-(4x²+28x+49)
=9x²-30x+25-4x²-28x-49
=5x²-58x-24
2.(x+y+1)(x+x-1)
=[(x+y)+1][(x+y)-1]
=(x+y)²-1²
=x²+2xy+y²-1
3.(2x-y-3)平方
=[(2x-y)-3]²
=(2x-y)²-2×3×(2x-y)+3²
=4x²-4xy+y²-12x+6y+9
4.[(x+2)(x-2)]平方
=(x²-4)²
=x4次方-8x²+16
推荐
猜你喜欢
© 2025 79432.Com All Rights Reserved.
电脑版|手机版