Question

数学题 运用乘法公式计算~高手来啊~

1.(三分之二X-y)(三分之二X+y)
2.(2a-3b)(3b+2a)
3.(-2b-5)(2b-5)
4.(2a+5b)^2
5.(3X-5)^2-(2X+7)^2
6.4(x+1)^2-(2x+5)(2x-5)
7.63^2
8.998*102

Answer 1

1.(三分之二X-y)(三分之二X+y)  =        4/9  x^2-y^2

2.(2a-3b)(3b+2a)  =    4a^2 -9b^2

3.(-2b-5)(2b-5)    =  4b^2-25

4.(2a+5b)^2      =  4a^2+20ab+25b^2

5.(3X-5)^2-(2X+7)^2=(9x^2-30x+25)-(4x^2+28x+49)=5x^2-58x-24

6.4(x+1)^2-(2x+5)(2x-5)=4(x^2+x+1)-( 4x^2-25)=4x+29

7.63^2=(60+3)^2 =3600+360+9=3969

8.998*1002=(1000-2)(1000+2)=1000000-4=999996

Answer 2

（1）原式=(2/3x)²-y²
=4/9x²-y²
(2)原式=(2a+3b)(2a-3b)
=(2a)²-(3b)²
=4a²-9b²
(3)原式=(-5+2b)(-5-2b)
=(-5)²-(2b)²
=25-4b²
(4)原式=(2a)²+2×2a×5b+(5b)²
=4a²+20ab+25b²
(5)原式=[(3x-5)+(2x+7)][(3x-5)-(2x+7)]
=(5x+2)(x-12)
=5x²-60x+2x-24
=5x²-58x-24
(6)原式=4(x²+2x+1)-(4x²-25)
=4x²+8x+4-4x²+25
=8x+29
(7)原式=(60+3)²
=60²+2×60×3+3²
=3600+360+9
=3969
(8)原式=(1000-2)(1000+2)
=1000²-2²
=1000000-4
=999996
其中第八题题目应该写错了。

Answer 3

1·=4/9X^2-Y^2
(2a-3b)(3a+2b)
= (2a-3b)(2a+3b)
=4a^2-9b^
3.(-2b-5)(2b-5)
= -(2b+5)(2b-5)
= -(4b^2-25)
= -4b^2+25
4.(2a+5b)^2
= 4a^2+20ab=25b^2
5.(3x-5)^2-(2x+7)^2
=[3x-5+2x+7][3x-5-2x-7]
7.63^2
=（60+3）^2
=360+360+9
=729
8.998*102
=(100-2)(100+2)
=10000-4
=9996
(第六题不会做，见谅）

Answer 4

“ ^ ”什么意思啊？