公式
1.已知志雄每月的改入($L)可由公式 I=6000+S/5求出,其中$S代表該月的銷售額.
(a)把上述公式的主項變換為S.
(b)如果志雄九月份的改入是$7700,求他該月份的銷售額.
恆等及因式分解
證明:
(a)2(x+7)=2(x+5)+4
(b)8(2x-3)=-4(6-4x)
展開:
(1) (x+7)^2
(2) (3y+1)^2
(3) (10+z)^2
(4) (x-5)^2
(5) (4y-1)^2
(6) (5-3z)^2
分解為因式:
(1) 4c-6d+8
(2) 2a^2-2a+b-ab
(3) 4a^2-1
(4) 9x^2-12xy+4y^2
(5) m^2+10mn+25n^2
(6) 2x^2-8y^2
(7) (3-m)^2-144
(8) (x+2y)^2-9y^2
解方程:
(1)[8x-3y=7 (2)[x=1/2y+4
[8x+5y=-1 [x-y=1
help me now?Maths=超難
2011-01-02 10:46 pm
回答 (2)
2011-01-03 1:37 am
✔ 最佳答案
1. S=5(I-6000)2. S=5(7700-6000)
=5*1700
=8500
3. 2(X+7)=2(X+5)+4
2X+14=2X+10+4
2X+14=2X+14
4. 8(2x-3)=-4(6-4x)
16X-24=-24+16X
展開:
1.X^2+14X+49
2.9Y^2+6Y+1
3.100+20Z+Z^2
4.X^2-10X+25
5.16Y^2-8Y+1
6.25-30Z+9Z^2
分解為因式:
2(2C-3B+4)
(2A-B)(A-1)
(2A+1)(2A-1)
(3X-2Y)^2
(M+5N)^2
(!2 X+2!2 Y)(!2 X-2!2 Y) !為根號
[(3-M)+12][(3-M)-12]
[(X+2Y)+3Y][(X+2Y)-3Y]
解方程:
1. X=0.5 Y=-1
2. X=7 Y=6
2011-01-03 1:44 am
你好～～～
以下都是敝人的答案～～
1) L=6000+S/5
a) Sol: L = 6000 + S / 5
L - 6000 = S / 5
S = 5(L - 6000)
b) Sol: S = 5(7700 - 6000) = 5 x 1700 = $8500
a) 2(x + 7) = 2(x + 5) + 4
L.H.S. = 2(x + 7) = 2x + 14
R.H.S. = 2(x + 5) + 4 = 2x + 10 + 4 = 2x + 14
L.H.S. = R.H.S.
b) 8(2x-3)=-4(6-4x) L.H.S. = 8(2x – 3) = 16x – 24 R.H.S. = -4(6 – 4x) = -24 + 16x = 16x – 24 L.H.S. = R.H.S.
(1) (x+7)^2 Sol: (x + 7)^2 = x^2 + 2(x)(7) + 7^2 = x^2 + 14x + 49
(2) (3y+1)^2 Sol: (3y + 1)^2 = (3y)^2 + 2(3y)(1) + 1^2 = 9y^2 + 6y + 1
(3) (10+z)^2 Sol: (10 + z)^2 = 10^2 + 2(10)(z) + z^2 = z^2 + 20z + 100
(4) (x-5)^2 Sol: (x – 5)^2 = x^2 – 2(5)(x) + 5^2 = x^2 – 10x + 25
(5) (4y-1)^2 Sol: (4y – 1)^2 = (4y)^2 – 2(4y)(1) + 1^2 = 16y^2 – 8y + 1
(6) (5-3z)^2 Sol: (5 – 3z)^2 = 5^2 – 2(5)(3z) + (3z)^2 = 9z^2 – 30z + 25
(1) 4c-6d+8 Sol: 4c – 6d + 8 = 2(2c – 3d + 4)
(2) 2a^2-2a+b-ab Sol: 2a^2 – 2a + b – ab = 2a(a – 1) + b(1 – a) = 2a(a – 1) – b(a – 1) = (a – 1)(2a – b)
(3) 4a^2-1 Sol: 4a^2 – 1 = (2a)^2 – 1^2 = (2a + 1)(2a – 1)
(4) 9x^2-12xy+4y^2 Sol: 9x^2 – 12xy + 4y^2 = (3x)^2 – 2(3x)(2y) + (2y)^2 = (3x – 2y)^2
(5) m^2+10mn+25n^2 Sol: m^2 + 10mn + 25n^2 = m^2 + 2(m)(5n) + (5n)^2 = (m + 5n)^2
(6) 2x^2-8y^2 Sol: 2x^2 – 8y^2 = 2(x^2 – 4y^2) = 2[x^2 – (2y)^2] = 2(x + 2y)(x -2y)
(7) (3-m)^2-144 Sol: (3 – m)^2 – 144 = (3 – m)^2 – 12^2 = (3 – m + 12)(3 – m – 12) = (15 – m)(-9 – m) = -(15 – m)(9 + m)
(8) (x+2y)^2-9y^2 Sol: (x + 2y)^2 – 9y^2 = (x + 2y)^2 – (3y)^2 = (x + 2y + 3y)(x + 2y – 3y) = (x + 5y)(x – y)
(1)[8x-3y=7………(1) [8x+5y=-1………(2) (1) – (2): -8y = 8 y = -1………(3) 放(3)進(1): 8x – 3(-1) = 78x + 3 = 7 8x = 4 x = 1/2 (2)[x=1/2y+4………(1) [x-y=1………(2) 放(1)進(2): y/2 + 4 – y = 1-y/2 = 1 – 4 y/2 = 3 y = 6………(3) 放(3)進(2): x – 6 = 1x = 7
希望可以幫到你～～～～～
以下都是敝人的答案～～
1) L=6000+S/5
a) Sol: L = 6000 + S / 5
L - 6000 = S / 5
S = 5(L - 6000)
b) Sol: S = 5(7700 - 6000) = 5 x 1700 = $8500
a) 2(x + 7) = 2(x + 5) + 4
L.H.S. = 2(x + 7) = 2x + 14
R.H.S. = 2(x + 5) + 4 = 2x + 10 + 4 = 2x + 14
L.H.S. = R.H.S.
b) 8(2x-3)=-4(6-4x) L.H.S. = 8(2x – 3) = 16x – 24 R.H.S. = -4(6 – 4x) = -24 + 16x = 16x – 24 L.H.S. = R.H.S.
(1) (x+7)^2 Sol: (x + 7)^2 = x^2 + 2(x)(7) + 7^2 = x^2 + 14x + 49
(2) (3y+1)^2 Sol: (3y + 1)^2 = (3y)^2 + 2(3y)(1) + 1^2 = 9y^2 + 6y + 1
(3) (10+z)^2 Sol: (10 + z)^2 = 10^2 + 2(10)(z) + z^2 = z^2 + 20z + 100
(4) (x-5)^2 Sol: (x – 5)^2 = x^2 – 2(5)(x) + 5^2 = x^2 – 10x + 25
(5) (4y-1)^2 Sol: (4y – 1)^2 = (4y)^2 – 2(4y)(1) + 1^2 = 16y^2 – 8y + 1
(6) (5-3z)^2 Sol: (5 – 3z)^2 = 5^2 – 2(5)(3z) + (3z)^2 = 9z^2 – 30z + 25
(1) 4c-6d+8 Sol: 4c – 6d + 8 = 2(2c – 3d + 4)
(2) 2a^2-2a+b-ab Sol: 2a^2 – 2a + b – ab = 2a(a – 1) + b(1 – a) = 2a(a – 1) – b(a – 1) = (a – 1)(2a – b)
(3) 4a^2-1 Sol: 4a^2 – 1 = (2a)^2 – 1^2 = (2a + 1)(2a – 1)
(4) 9x^2-12xy+4y^2 Sol: 9x^2 – 12xy + 4y^2 = (3x)^2 – 2(3x)(2y) + (2y)^2 = (3x – 2y)^2
(5) m^2+10mn+25n^2 Sol: m^2 + 10mn + 25n^2 = m^2 + 2(m)(5n) + (5n)^2 = (m + 5n)^2
(6) 2x^2-8y^2 Sol: 2x^2 – 8y^2 = 2(x^2 – 4y^2) = 2[x^2 – (2y)^2] = 2(x + 2y)(x -2y)
(7) (3-m)^2-144 Sol: (3 – m)^2 – 144 = (3 – m)^2 – 12^2 = (3 – m + 12)(3 – m – 12) = (15 – m)(-9 – m) = -(15 – m)(9 + m)
(8) (x+2y)^2-9y^2 Sol: (x + 2y)^2 – 9y^2 = (x + 2y)^2 – (3y)^2 = (x + 2y + 3y)(x + 2y – 3y) = (x + 5y)(x – y)
(1)[8x-3y=7………(1) [8x+5y=-1………(2) (1) – (2): -8y = 8 y = -1………(3) 放(3)進(1): 8x – 3(-1) = 78x + 3 = 7 8x = 4 x = 1/2 (2)[x=1/2y+4………(1) [x-y=1………(2) 放(1)進(2): y/2 + 4 – y = 1-y/2 = 1 – 4 y/2 = 3 y = 6………(3) 放(3)進(2): x – 6 = 1x = 7
希望可以幫到你～～～～～
參考: Yogi
收錄日期: 2021-04-13 17:44:32
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https://hk.answers.yahoo.com/question/index?qid=20110102000051KK00630