1) \(\left(x-5\right)\left(x+7\right)-7x\left(x+3\right)\)
\(=x^2+7x-5x-35-7x^2-21x\)
\(=-6x^2-19x-35\)
2) \(\left(x+5\right)\left(x+7\right)-\left(x-4\right)\left(x+3\right)\)
\(=x^2+5x+7x+35-\left(x^2+3x-4x-12\right)\)
\(=x^2+12x+35-x^2+x+12\)
\(=13x+47\)
3) \(\left(2x-3\right)\left(x+4\right)+\left(-x+1\right)\left(x-2\right)\)
\(=2x^2+8x-3x-12-x^2+2x+x-2\)
\(=x^2+8x-14\)
Câu 1: Cho f(x) = −2x
4 + 3x
3 − 4x
2 + x − 7 và g(x) = −x
4 + 2x
3 − 3x
2 − x
3 + 3x
4 − 17. Khi
đó M(x) = f(x) + g(x)
Câu 2: Cho đa thức f(x) = −x
4 + 2x
3 − 5x
2 + 7x − 3 và g(x) = −3x
4 + 2x
3 − 7x + 5. Biết
M(x) = f(x) − g(x). Tính M(1) =?
Bài 1. Tìm \(x\).
a) -5(\(x\)2-3\(x\)+1)+\(x \)(1+5\(x\))=\(x-2\)
b) \(12x\)2\(-4x\)\((3x+5)\)\(=10x-17\)
c) \(-4x(x-5)+7x(x-4)-3x\)2\(=12\)
Bài 2. Tính ( Rút gọn).
a) \((x+5).(x-7)-7x.(x-3)\)
b) \(x.(x\)2\(-x-2)-(x-5).(x+1)\)
c) \((x-5).(x-7)-.(x+4).(x-3)\)
d) \((x-1).(x-2)-(x+5).(x+2)\)
Tìm số hữu tỉ x biết
a) (x-3)/5=6-(1/3)+[(1/3)*x]
b)[(1/2)*x]-(1/3)-5=[3-2x+7)]/4
c) [(7x)/8]-5x+45=(10/3)*x+1/4
d) [(4-x)/2007]=(7-x/2004)-(9-x/2002)-1
Tìm x, biết :
1) x+1 / x-2 = 3/4
2) 2x - 3 / x+1 = 4/7
3) 2x + 3 / 7 = 4x-1/15
4) 11x - 2 / 7x + 5 = 11/8
5) 12 - 7x / -13 = 4 - 3x / -5
Bài 1: Tìm x, biết
a) 3/7x - 2/3x =10/21
b) 7/35 : ( x- 1/3)=2/25
c) | 2x-4 |+1=5
d) 3.| 3 - 2x | - 1=2/5
e) 3.(x-1/2)-5(x+3/5)=-x+1/5
f) (2x-1).(x+2/3)=0
g) x+4/2008+x+3/2009=x+2/2010+x+1/2011
Tìm X:
a, 3/7- (2/5 + X + 3/2) = 5/14 - /4/35 - (-11)/70 /
b,3/4(x-8) = 5/7.(4-1/2)
c,3/2 - 4(1/4 - x) = 2/3 - 7x
d,4.(1/2-x) - 5.(x-3/10) = 7/4
a, 4x(x2-x-1)-(x2-2)(x+3)
b, (x+5)(x+7)-7x(x+3)
c, x(x2-x-2)-(x+5)(x-1)
d, (x+5)(x+7)-(x-4)(x+3)
Thu gọn các đơn thức đồng dạng trong đa thức sau:
a) \(A=x^5-\dfrac{1}{2}x+7x^3-2x+\dfrac{1}{5}x^3+3x^4-x^5+\dfrac{2}{5}x^4+15\)
b) \(B=3x^2-10+\dfrac{2}{5}x^3+7x-x^2+8+7x^2\)
c) \(C=\dfrac{1}{7}x-2x^4+5x+6\)
TÌM X, BIẾT:
a) 3 . ( 1/2 - x ) + 1/3 = 7/6 - x
b) 4 . ( 1/2 - x ) - 5 . ( x - 3/10 ) = 7/4
c) -3/2 . ( 4/5 - 2/3 ) + x = 4 . ( x - 1/2 )
d) 2 . ( 3/2 - x ) - 1/3 = 7x - 1/4
e) 1/5 . ( -3/5 -10 ) + 5x = x - 2/3
f) -3/2 . ( 5 - 1/6 ) + 4 . ( x - 1/2 ) = 1
~ PLEASE HELP ME ~
