x-1/2=2y+1/5=3x-4y-5
x-1/2=2y+1/5=3x-4y-5/2x
tìm x, y
bài 5 đa thức N thỏa mãn điều kiện
a) (3x^5-4x^4+6x^3)=(-2x^2).N b) N.(-1/3x^2y^3)=6x^4y^5-3x^3y^4+1/2x^4y^3z c) x^3-3x^2y+3xy^2-y^3=N.(y-x) d) x^4-2x^2y^2+y^4=(y^2-x^2).N
a: \(N=\dfrac{3x^5-4x^4+6x^3}{-2x^2}=-\dfrac{3}{2}x^3+2x^2-3x\)
b: \(N=\dfrac{\left(6x^4y^5-3x^3y^4+\dfrac{1}{2}x^4y^3z\right)}{-\dfrac{1}{3}x^2y^3}=-18x^2y^2+9xy-\dfrac{3}{2}x^2z\)
c: \(\Leftrightarrow N\cdot\left(y-x\right)=\left(x-y\right)^3\)
\(\Leftrightarrow N=\dfrac{\left(x-y\right)^3}{y-x}=-\left(y-x\right)^2\)
d: \(\Leftrightarrow N\cdot\left(y^2-x^2\right)=\left(y^2-x^2\right)^2\)
hay \(N=y^2-x^2\)
1. x^2-y^2-2x+2y 2. x^3-x+3x^2y+3xy^2+y^3-y. 3. 4x^4y^4+1. 4. x^2-2x-4y^2-4y. 5.x^3-x^2-x+1. 6.x^2y-x^3-9y+9x. 7.x^3-2x^2+x-xy^2. 8.x^2-2x-4y^2-4y.
Ói , hoa mắt chóng mặt nhức đầu ,
Question Expandand simplify: 1. 8(x+5)-3(2x+7)
2. a(2b+c)+b(3c-2a)
3. 2y(y+5x)+x(3x+4y)
answer , 1. 8(x+5)-3(2x+7)=8x+40-6x+21=2x+61
2. a(2b+c)+b(3c-2a)=2ab+ac+3bc-2ab=ac+3bc=3abc^(2)
3. 2y(y+5x)+x(3x+4y)=2y^(2)+10xy+9x^(2)+4xy=9x^(2)+2y^(2)+14xy
a Explain what he has done wrong.
b work out the correct answer
Bài 2: Phân tích đa thức sau thành nhân tử.
a) 3x(x +1) – 5y(x + 1) h) 3x3(2y – 3z) – 15x(2y – 3z)2
b) 3x(x – 6) – 2(x – 6) k) 3x(z + 2) + 5(-x – 2)
c) 4y(x – 1) – (1 – x) l) 18x2(3 + x) + 3(x + 3)
d) (x – 3)3 + 3 – x m) 14x2y – 21xy2 + 28x2y2
e) 7x(x – y) – (y – x) n) 10x(x – y) – 8y(y – x)
a) 3x(x + 1) - 5y(x + 1)
= (x + 1)(3x - 5y)
b) 3x(x - 6) - 2(x - 6)
= (x - 6)(3x - 2)
c) 4y(x - 1) - (1 - x)
= 4y(x - 1) + (x - 1)
= (x - 1)(4y + 1)
d) (x - 3)³ + 3 - x
= (x - 3)³ - (x - 3)
= (x - 3)[(x - 3)² - 1]
= (x - 3)(x - 3 - 1)(x - 3 + 1)
= (x - 3)(x - 4)(x - 2)
e) 7x(x - y) - (y - x)
= 7x(x - y) + (x - y)
= (x - y)(7x + 1)
h) 3x³(2y - 3z) - 15x(2y - 3z)²
= (2y - 3z)[3x³ - 15x(2y - 3x)]
= 3x(2y - 3x)[x² - 5(2y - 3x)]
= 3x(2y - 3x)(x² - 10y + 3x)
= 3x(2y - 3x)(x² + 3x - 10y)
k) 3x(x + 2) + 5(-x - 2)
= 3x(x + 2) - 5(x + 2)
= (x + 2)(3x - 5)
l) 18x²(3 + x) + 3(x + 3)
= (x + 3)(18x² + 3)
= 3(x + 3)(6x² + 1)
m) 7x(x - y) - (y - x)
= 7x(x - y) + (x - y)
= (x - y)(7x + 1)
n) 10x(x - y) - 8y(y - x)
= 10x(x - y) + 8y(x - y)
= (x - y)(10x + 8y)
= 2(x - y)(5x + 4y)
Tìm bậc của các đa thức sau:
a) \(x^3y^3+6x^2y^2+12xy-8
\)
b) \(x^2y+2xy^2-3x^3y+4xy^5\)
c) \(x^6y^2+3x^6y^3-7x^5y^7+5x^4y\)
d) \(2x^3+x^4y^5+3xy^7-x^4y^5+10-xy^7\)
e) \(0,5x^2y^3+3x^2y^3z^3-a.x^2y^3-x^4-x^2y^3\) với a là hằng số
a, bậc 6
b, bậc 6
c, bậc 12
d, bậc 9
e, bậc 8
Bài 2: Phân tích thành nhân tử:
b) (x+2)2-25
c) 36(x-y)2
d) x2+1/2x+1/16
e) 2x4y3-3x2y4+5x3y4
f) 3x(x-2)+5(2-x)
g) 3x(x-2y)+6y(2y-x)
i) x(x-1)+(1-x)2
k) 2y(x+2)-3x-6
l) x2+6x-3(x+6)
m) xy+x-2y-2
n) 3x2-3xy-5x+5y
15) x3-8/125
16) x2-x-y2-yy
17) x3+4x-(y3+4y)
18) 5x-√5x+1/4
19) x3+2x2+x-16xy2
20) (x+2y)2-(x-y)
21) (9x2-33x3x+2y+-4y2
22) 9x2-6xy+3x-y+y2
\(b,\left(x+2\right)^2-25\)
\(=\left(x+2\right)^2-5^2\)
\(=\left(x-3\right)\left(x+7\right)\)
\(c,36\left(x-y\right)^2\)
\(=36\left(x^2-2xy+y^2\right)\)
\(=36x^2-72xy+36y^2\)
\(d,x^2+\dfrac{1}{2}x+\dfrac{1}{16}\)
\(=x^2+2.x.\dfrac{1}{4}+\dfrac{1}{4}^2\)
\(=\left(x+\dfrac{1}{4}\right)^2\)
\(e,2x^4y^3-3x^2y^4+5x^3y^4\)
\(=x^2y^3\left(2x^2-3y+5xy\right)\)
Các câu còn lại làm tương tự, chú ý sd HĐT
tìm x y biet 2/3x=3/4y, 2y=1/5 z va x+y+z=1
Bài1: Rút gọn các biểu thức sau
a, 3x^2-2x:(5+1,5x)+10
b, 7x(4y-x)+4y(y-7x)-2(2y^2-3,5x)
Bài2 : tìm x
a, 3(2x-1)-5(x-3) + 6(3x-4) =24
b, 2x^2 + 3(x^2-1) = 5x(x+1)
c,2x(5-3x) +2x(3x+5) - 3(x-7) =3