Giúp mk vs:
Tìm x,y thỏa mãn:
1> y=x^2+3x+7/x+3
2>y=4x+3/2x+6
3>y=3x/5-2x
4>y=4x+1/3x-1
5>x^2-2y=5-xy+2x
6>xy+12=x+y
P/s: / là Phần
Viết liền là nhân nha
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a) Xem lại đề
b) x³ - 4x²y + 4xy² - 9x
= x(x² - 4xy + 4y² - 9)
= x[(x² - 4xy + 4y² - 3²]
= x[(x - 2y)² - 3²]
= x(x - 2y - 3)(x - 2y + 3)
c) x³ - y³ + x - y
= (x³ - y³) + (x - y)
= (x - y)(x² + xy + y²) + (x - y)
= (x - y)(x² + xy + y² + 1)
d) 4x² - 4xy + 2x - y + y²
= (4x² - 4xy + y²) + (2x - y)
= (2x - y)² + (2x - y)
= (2x - y)(2x - y + 1)
e) 9x² - 3x + 2y - 4y²
= (9x² - 4y²) - (3x - 2y)
= (3x - 2y)(3x + 2y) - (3x - 2y)
= (3x - 2y)(3x + 2y - 1)
f) 3x² - 6xy + 3y² - 5x + 5y
= (3x² - 6xy + 3y²) - (5x - 5y)
= 3(x² - 2xy + y²) - 5(x - y)
= 3(x - y)² - 5(x - y)
= (x - y)[(3(x - y) - 5]
= (x - y)(3x - 3y - 5)
Bài 2:
c: \(=x^2\left(x-3\right)-4\left(x-3\right)\)
\(=\left(x-3\right)\left(x-2\right)\left(x+2\right)\)
1) 2x + 2y - x(x+y)
= 2(x + y) - x(x + y)
= (2 - x)(x + y)
2/ 5x2 - 5xy -10x + 10y
= 5x(x - y) - 10(x - y)
= (5x - 10(x - y)
3/ 4x2 + 8xy - 3x - 6y
= 4x(x + 2y) - 3(x + 2y)
= (4x - 3)(x + 2y)
1) 2x + 2y - x(x + y)
= 2(x + y) - x(x + y)
= (2 - x)(x + y)
2) 5x2 - 5xy - 10x + 10y
= 5x(x - y) - 10(x - y)
= (5x - 10)(x - y)
= 5(x - 2)(x - y)
3) 4x2 + 8xy - 3x - 6y
= 4x(x + 2y) - 3(x + 2y)
= (4x - 3)(x + 2y)
4) 2x2 + 2y2 - x2z + z - y2z - 2
= 2(x2 + y2 - z(x2 + y2) - (2 - z)
= (2 - z)(x2 + y2) - (2 - z)
= (2 - z)(x2 + y2)
5) x2 + xy - 5x - 5y
= x(x + y) - 5(x + y)
= (x - 5)(x + y)
6) x(2x - 7) - 4x + 14
= x(2x - 7) - 2(2x - 7)
= (x - 2)(2x - 7)
7)x2 - 3x + xy - 3y
= x(x + y) - 3(x + y)
= (x - 3)(x + y)
1)\(y=\frac{x^2+3x+7}{x+3}=\frac{x\left(x+3\right)+7}{x+3}=x+\frac{7}{x+3}\)= > x +3 thuoc\(U_{\left(7\right)}=\left\{1;-1;7;-7\right\}\)
x thuoc \(\left\{-2;-4;3;-11\right\}\)
2)\(y=\frac{4x+3}{2x+6}=\frac{4x+12-8}{2x+6}=\frac{2\left(2x+6\right)-8}{2x+6}=2-\frac{8}{2x+6}\) =>2x+6 thuoc
\(U_{\left(8\right)}=\left\{1;-1;2;-2;4;-4;8;-8\right\}\)
=>x thuoc \(\left\{-2;-4;-1;-5;1;-7\right\}\)
4)\(y=\frac{4x+1}{3x-1}\)
\(3y=\frac{12x+3}{3x-1}=\frac{12x-4+7}{3x-1}=\frac{4\left(3x-1\right)+7}{3x-1}=4+\frac{7}{3x-1}\)
3x+1 thuoc {1;-1;7;-7}
3x thuoc {0;-2;6;-8}
x thuoc {0;2}