中一MATHS(10)

1.化簡(a+a)(a+a+a)

(a+a)(a+a+a)
= 2a* 3a
= 2* 3* a^2
= 6a^2

2.化簡20d^5/5d^3x2d

20d^5/5d^3x2d
= 20d^5/ 10d^4
= 20/10 * d^5/ d^4
= 2* d
= 2d


3.展開(2c一3)(5c+1)

(2c一3)(5c+1)
= (2c* 5c + 2c) -(15c+3)
= 10c^2 -15c+ 2c-3
= 10c^2 -13c -3


4.解方程 6一2y=10

6一2y=10
2y=10- 6
y= 4/2
y=4

I really hope you will choose me!!
thanks!!

2007-09-16 20:12:06 補充：
sorry!! i made a careless mistake on 4.it should be:6一2y=10 6 = 10 2y 6- 10= 2y -4/2= y y= -2sorry!!

1. (a+a)(a+a+a)
=(2a)(3a)
=(6a^2)

2. 20d^5/5d^3x2d
=20d^5/10d^4
=2d

3. (2c-3)(5c+1)
=10c^2+2c-15c-3
=10c^2-13c-3

4. 6-2y=10
2y=6-10
2y= -4
y= -2

希望可以幫到你=]

1 (a+a)(a+a+a)
=2a x 3a
=6a

2 20d^5/5d^3x2d
=4d^ x 2d
=8d^3

3 (2c一3)(5c+1)
=10c^2一15c+2c一3
=10c^2一13c一3

4 6一2y=10
6一2y一6=10一6
2y=4
y=2

double check it
i might be wrong y'know

(a+a)(a+a+a)
=a^2+a^2+a^2+a^2+a^2+a^2
=6a^2

20d^5/5d^3x2d
=20d^5/10d^5
=10d^2

(2c一3)(5c+1)
=10c+2c－15c-3

6一2y=10
-2y=4
y=-2

1.
(a+a)(a+a+a)
=2a×3a
=6a^2

2.
20d^5/5d^3x2d
=4d^2×2d
=8d^3

3.
(2c一3)(5c+1)
=2c(5c+1)-3(5c+1)
=10c^2+2c-15c-3
=10c^2-13c-3

4.
6一2y=10
6-10=2y
-4=2y
y=-2