help me with some math homework?
1: Factor each completely:
x2 - 64
(x - 8)2
(x - 16)(x - 4)
(x + 8)(x - 8)
2: x2 + 4x + 4
(x + 2)2
(x + 4)(x + 1)
(x - 2)(x + 2)
3: 25x2 - 30x + 9
(5x - 3)2
5(x + 3)(x - 3)
(5x + 3)(5x - 3)
4: 4x2 - 144
4(x - 6)2
4(x - 6)( x + 6)
(4x - 12)(x + 12)
5: 36x2 - 12x + 1
(6x - 1)2
(6x - 1)(6x + 1)
(6x - 4)(6x + 3)
6: 6b2c3 - 18b2c2d2
6bc (c - 3d)
6b2c2d2(c - 3)
6b2c2(c - 3d2)
7: 4x4 + 40x3
(4x2 + x)(10x2 + x2)
4x3(x + 10)
(4x2 + x)2
8: x2 - 6x + 9
(x - 3)(x + 3)
(x - 3)2
(x - 2)(x - 4)
9: x2 - 121
(x - 11)(x + 11)
(x - 11)2
(x + 11)2
10: x2 + 8x + 16
(x + 16)(x + 1)
(x + 16) (x - 8)
(x + 4)2
11: x2 - 22x + 121
(x - 11)2
(x - 11)(x + 11)
(x + 11)2
12: 49x2 - 64
(7x - 8)(7x + 8)
7(x2 - 9)
7(x - 3)(x + 3)
13: 16x2 - 25
(4x + 5) (4x - 5)
(4x - 5)2
(4x + 5)2
14: 49x2 - 100
(7x +10)2
(7x - 10)2
(7x + 10) (7x - 10)
15: 9x2 + 48x + 64
(3x + 8)2
(3x - 8)2
(3x + 8)(3x - 8)
16: 6x2 - 60x + 150
6(x + 5)2
6(x - 5)2
(6x - 5)2
17: 7x2 - 63
7(x + 3)(x - 3)
7(x + 3)2
7(x - 3)2
18: Solve these by factoring:
2r2 - 162 = 0
r = 0, -9, 9
r = -9, 9
r = 2, -9, 9
19: 3x3 - 3x = 0
x = 1
x = -1, 1
x = -1, 0, 1
20: 81x2 + 180x + 100 = 0
x = -9, -10
x = -10/9
x = 0, 9, 10
回答 (9)
✔ 最佳答案
1: (x + 8)(x - 8)
2: (x + 2)2
3: (5x - 3)2
4: 4(x - 6)( x + 6)
5: (6x - 1)2
6: 6b2c2(c - 3d2)
7: 4x3(x + 10)
8: (x - 3)2
9: (x - 11)(x + 11)
10: (x + 4)2
11: (x - 11)2
12: (7x - 8)(7x + 8)
13: (4x + 5) (4x - 5)
14: (7x + 10) (7x - 10)
15: (3x + 8)2
16: 6(x - 5)2
17: 7(x + 3)(x - 3)
18:
2r2 - 162 = 0
2(r^2 - 81) = 0
2(r+9)(r-9) = 0
r = -9, 9
19:
3x3 - 3x = 0
3x(x^2 - 1) = 0
3x(x+1)(x-1) = 0
x = -1, 1
20: 81x2 + 180x + 100 = 0
(9x + 10)(9x + 10) = 0
x = -10/9
1)(x+8)(x-8)
2)(x+2)2
3)(x-5)2
4)4(x-6)(x+6)
5)(6x-1)2
6)6bc2-18bcd
7)4x3(x+10)
8)(x-3)2
9)(x-11)(x+11)
10)(x+4)2
11)(x-11)2
12)(7x-8)(7x+8)
13)(4x+5)(4x-5)
14)(7x+10)(7x-10)
15)(3x+8)2
16)6(x-5)2
17)7(x+3)(x-3)
18)r=9,-9
19) x= -1 0 1
20) x= -10/9
1)(x+8)(x-8)
2)(x+2)^2
3)(5x-3)^2
4)4(x+12)(x-12)
5)(6x-1)^2
6)6b^2c^2(c-3d^2)
7)4x^3(x+10)
8)(x-3)^2
9)(x+11)(x-11)
10)(x+4)^2
11)(x-11)^2
12)(7x+8)(7x-8)
13)(4x+5)(4x-5)
14)(7x+10)(7x-10)
15)(3x+8)^2
16)6(x-5)^2
17)7(x+3)(x-3)
18)-9 ,+9
19)-1 ,0, +1
20)-10/9
a^2 - b^2 = (a + b)(a - b)
1)
x^2 - 64
= (x + 8)(x - 8)
2)
x^2 + 4x + 4
= (x + 2)(x + 2)
= (x + 2)^2
3)
25x^2 - 30x + 9
= (5x - 3)(5x - 3)
= (5x - 3)^2
4)
4x^2 - 144
= 4(x^2 - 36)
= 4(x + 6)(x - 6)
5)
36x^2 - 12x + 1
= (6x - 1)(6x - 1)
= (6x - 1)^2
6)
6b^2c^3 - 18b^2c^2d^2
= 6(b^2c^3 - 3b^2c^2d^2)
= 6b^2c^2(c - 3d^2)
7)
4x^4 + 40x^3
= 4(x^4 + 10x^3)
= 4x^3(x + 10)
8)
x^2 - 6x + 9
= (x - 3)(x - 3)
= (x - 3)^2
9)
x^2 - 121
= (x + 11)(x - 11)
10)
x^2 + 8x + 16
= (x + 4)(x + 4)
= (x + 4)^2
11)
x^2 - 22x + 121
= (x - 11)(x - 11)
= (x - 11)^2
12)
49x^2 - 64
= (7x + 8)(7x - 8)
13)
16x^2 - 25
= (4x + 5)(4x - 5)
14)
49x^2 - 100
= (7x + 10)(7x - 10)
15)
9x^2 + 48x + 64
= (3x + 8)(3x + 8)
= (3x + 8)^2
16)
6x^2 - 60x + 150
= 6(x^2 - 10x + 25)
= 6(x - 5)(x - 5)
= 6(x - 5)^2
17)
7x^2 - 63
= 7(x^2 - 9)
= 7(x + 3)(x - 3)
= = = = = = = =
18)
2r^2 - 162 = 0
(2r^2 - 162)/2 = 0/2
r^2 - 81 = 0
(r + 9)(r - 9) = 0
r + 9 = 0
r = -9
r - 9 = 0
r = 9
ⴠr = ±9
= = = = = = = =
19)
3x^3 - 3x = 0
(3x^3 - 3x)/3 = 0/3
x^3 - x = 0
x(x^2 - 1) = 0
x(x + 1)(x - 1) = 0
x = 0
x + 1 = 0
x = -1
x - 1 = 0
x = 1
ⴠx = 0 , ±1
= = = = = = = =
20)
81x^2 + 180x + 100 = 0
(9x + 10)(9x + 10) = 0
9x + 10 = 0
9x = -10
x = -10/9
â´ x = -10/9
3: 25x2 - 30x + 9
25 times 9 is 225
find two numbers whose product is 225 and whose sum is -30.
-15,-15
25x^2-30x+9
=25x^2-15x-15x+9
5x(5x-3)-3(5x-3)
(5x-3)(5x-3)
(5x-3)^2
16: 6x2 - 60x + 150
product 900
sum -60
the numbers are -30,-30
6x^2-30x-30x+150
6x(x-5)-30(x-5)
(x-5)(6x-30)
(x-5)6(x-5)
6(x-5)(x-5)
6(x-5)^2
Go into start --- search --- type 'Calculator' and work away!
Try not to cause too much strain on your poor fingers !
He still doesn't know how to do the math now, since he was given the answers, and now he'll have a false grade on his homework, which will hide the fact he still doesn't know how to do it.
Lousy parents make lousy homeschooling parents.
Lousy people make lousy public school teachers....
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