Ta có: \(P\left(x\right)=x^2+5x^4-3x^3+x^2+4x^4+3x^3-x+5\)
\(=9x^4+2x^2-x+5\)
Ta có: \(Q\left(x\right)=x-5x^3-x^2-x^4+4x^3-x^2-3x-1\)
\(=-x^4-x^3-2x^2-2x-1\)
Ta có: P(x)+Q(x)
\(=9x^4+2x^2-x+5-x^4-x^3-2x^2-2x-1\)
\(=8x^4-x^3-3x+4\)
Ta có: P(x)-Q(x)
\(=9x^4+2x^2-x+5+x^4+x^3+2x^2+2x+1\)
\(=10x^4+x^3+4x^2+x+6\)
Tìm x:
1/3x(\(-\dfrac{4}{3}\)x+1)-4x(x-2)=10
2/5(x2-3x+1)+x(1-5x)=x-2
3/12x2-4x(3x-5)=10x-17
4/4x2-2x+3-4x(x-5)=7x-3
5/-3(x-5)+5(x-1)+3x2=4-x
Phân tích đa thức thành nhân tử
a) \(\left(x^2-x+1\right)\left(x^2+3x+1\right)+4x^2\)
b) \(x^3+5x^2+8x+4\)
Tìm x biết : (đề không sai)
1.\(-4x\left(x-7\right)+4x\left(x^2-5\right)\) \(=28x^2-13\)
2.\(\left(4x^2-5x\right)\left(3x+2\right)-7x\left(x-7\right)\)= \(\left(-4+x\right)\left(-2x+3\right)+12x^3+2x^2\)
3.\(\left(-4x^2-3\right)\left(2x+5\right)-\left(8x-3\right)\) \(\left(-x^2+2\right)=-5x^2\left(x-6\right)-3x^2-4\)
4.\(\left(x-7\right)\left(x+5\right)-\left(x-3\right)\left(x-2\right)\) \(=15x^2\left(x+1\right)-\left(3x^2-1\right)\) \(\left(5x^2-2\right)-21x^2\)
5.\(\left(x-3\right)\left(-x+10\right)+\left(x-8\right)\left(x+3\right)\) \(=\left(5x^2-1\right)\left(x+3\right)-5x^3-15x^2\)
6.\(\left(-2x^2+5\right)\left(-x+3\right)-x^2\left(2x-6\right)\) \(=\left(x-1\right)\left(x+1\right)-\left(x-2\right)\left(x+4\right)\)
1. (2x +3) (x- 5) +(X-4 ) + (x-5) ( x-2 0 = (3x -5) ( x-4)
2. (8x-3) (3x +2) - (4x+ 7) (x+4) = (2x + 1) (5x-1)
3. 2x^2 + (x -1) (x+1)= 5x (x+10
4. 4- ( x-1) (x+5) - (x+2) (x+5) = 3(x-1) (x+2)
Tính(rút gọn)
1, x^ 2 - 2x + 5 - (x - 7)(x + 2)
2,-5x(x-5)+(x-3)(x^2-7)
3, x(x^2-x-2)-(x+5)(x-1)
4, (-x+5)(x+3)+(2x-1)(x+3)
5, -4x(x+3)(x-4)-3x(x^2-x+1)
Rút gọn biểu thức
a) 3x² - 2x ( 5+ 1,5x ) + 10
b) ( x² - 2x + 3 ) ( x - 4 )
c) ( 5x + 2 ) ( 2x² - 3x - 1 )
d) ( 25x² + 10xy + 4y² ) ( 5x + 2y )
e) ( 5x³ - x² + 2x - 3 ) ( 4x² - x + 2 )
Bài 1: Thực hiện phép tính
a) (3x-1)(9x2+3x+1)-4x(x-5)
b) (7x+2)(3-4x)-(x+3)(x2-3x+9)
c) (4x+3)(4x-3)-(2-x)(4+2x+x2)
d) (3x-8)(-5x+6)-(4x+1)(3x-2)
e) (3x-6)4x-2x(3x+5)-4x2
f) (5x-6)(6x-5)-x(3x+10)
Bài 2 : Tính
a) x(x+3)-x2=6
b) 2x(x-5)+x(-2x-1)=6
c) x (x+5)-(x+1)(x-2)=7
d)(3x+4)(6x-3)-(2x+1)(9x-2)=10
Tìm nghiệm đa thức :
a) f(x) = (3x + 4) . (5x - 1) + (5x + 2) . (1 - 3x ) + 2
b) g(x) = (5x - 1) . (2x + 3) - 3.(3x - 1 )
Tìm nghiệm đa thức :
a) f(x) = (3x + 4) . (5x - 1) + (5x + 2) . (1 - 3x ) + 2
b) g(x) = (5x - 1) . (2x + 3) - 3.(3x - 1 )
