tìm x biết (4x-3)-(x+5) = (x+2)-2(x-10)
Tìm x biết; (4x-3)-(x+5)=(x+2)-2*(x+10)
Cho M(x) = 2x^5 - 4x^3 + 2x^2 + 10x - 1
và N(x) = -2x^5 + 2x^4 + 4x^3 + x^2 + x - 10
a/. Tính M(x) + N(x)
b/. Tìm A(x), biết A(x) + M(x) = N(x)
a/Ta có: M(x)+N(x) = (2x5 - 4x3 + 2x2 + 10x - 1) + (-2x5 + 2x4 + 4x3 + x2 + x - 10)
= 2x5 - 2x5 - 4x3 + 4x3 + 2x4 + 2x2 + x2 + 10x + x -1 - 10
= 2x4 + 3x2 + 11x - 11
b/ Ta có: A(x) = N(x)-M(x) = (-2x5 + 2x4 + 4x3 + x2 + x - 10) - (2x5 - 4x3 + 2x2 + 10x - 1)
= -2x5 - 2x5 + 2x4 + 4x3 + 4x3 + x2 - 2x2 + x - 10x -10 + 1
= -2x5 + 2x4 + 8x3 - x2 - 9x -9
Bài 3: Tìm x biết:
1, \(4x^2-36=0\)
2, \(\left(x-1\right)^2+x\left(4-x\right)=11\)
3, \(\left(x-5\right)^2-x.\left(x+2\right)=5\)
4, \(x\left(x+4\right)-x^2-6x=10\)
1: Ta có: \(4x^2-36=0\)
\(\Leftrightarrow\left(x-3\right)\left(x+3\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=3\\x=-3\end{matrix}\right.\)
2: Ta có: \(\left(x-1\right)^2+x\left(4-x\right)=11\)
\(\Leftrightarrow x^2-2x+1+4x-x^2=11\)
\(\Leftrightarrow2x=10\)
hay x=5
1. Tìm x biết:
a) | 3/2.x + 1/2 | = | 4x - 1 |
b) | 5/4.x - 7/2 | - | 5/8.x + 3/5 | = 10
c) | 7/5.x + 2/3 | = | 4/5.x - 1/4 |
a) \(\left|\frac{3}{2}x+\frac{1}{2}\right|=\left|4x-1\right|\)
\(\Rightarrow\orbr{\begin{cases}\frac{3}{2}x+\frac{1}{2}=4x-1\\\frac{3}{2}x+\frac{1}{2}=-4x+1\end{cases}}\Rightarrow\orbr{\begin{cases}4x-\frac{3}{2}x-1=\frac{1}{2}\\-4x-\frac{3}{2}x+1=\frac{1}{2}\end{cases}}\Rightarrow\orbr{\begin{cases}\frac{5}{2}x=\frac{3}{2}\\-\frac{11}{2}x=-\frac{1}{2}\end{cases}}\Rightarrow\orbr{\begin{cases}x=\frac{3}{5}\\x=\frac{1}{11}\end{cases}}\)
phần b ở đề bài mình ghi sai, là bằng 0 chứ ko phải bằng 10
tìm x thuộc Z biết:
1) 2(4x-8)-7(3+x)=[-4](3-2)
2) 12(x-4)+6(x-2)-16(x+3)=7[-4]
3) 4(x-5)-7(5-x)+10(5-x)=-3
4) -3[x+5]=15(-3)+7(-3)
5) 4[x-7]-3(-5)=-2[x-7]-10
1) <=> 8x-16-21-7x=-4
<=> x-37=-4
<=> x=33
2) <=> 12x-48+6x-12-16x-48=-28
<=> 2x-108=-28
<=> 2x = 80
<=> x = 40
3)<=> 4x-20-35+7x+50-10x=-3
<=> x-5=-3
<=> x=2
4) <=> -3x-15=-45-21
<=> 51=3x
<=> 17=x
5) 4x-28+15=-2x+14-10
<=> 6x-13=4
<=> 6x=17
<=> x = \(\frac{17}{6}\)
Chúc bạn học tốt
Tìm x, biết:
1) 2x . (x-5) -x . (2x-4) = 15
2) (x+1) . (x+2) - (x+4) . (x+3) = 6
3) 4x2 - 4x+5 - x . (4x-3) = 1-2x
4) (x+3) . (2x+1) - 2x2 = 4x-5
5) -4 . (2x-8) + (2x-1) . (4x+3) = 0
6) -3 . (x-2) + 4 . (2x-6) - 7 . (x-9)= 5 . (3-2)
7) (x-2) . (x+2) -2 . (x-4) = 10. 3x
8) 15x . (x-2) - (5x-1) . (3x + 1) = 6
9) (2x+4) . (x-3) - x . (2x-10) =15-20x
10) (4x-2) . (3x+4) - (2x-1) . (6x+5) = 100
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Tìm x, biết:
1) 2x ( x - 5) - x ( 2x - 4 ) = 15
<=> 2x2 - 10x - 2x2 + 4x - 15 = 0
<=> -6x - 15 = 0
<=> -6x = 15
<=> x = -15/6
2) ( x +1)( x + 2 ) - ( x + 4 ) ( x + 3 ) = 6
<=> x2 + 2x + x + 2 - x2 - 3x - 4x - 12 - 6 = 0
<=> -4x = -16
<=> x = 4
3) 4x2 - 4x + 5 - x ( 4x - 3) = 1 - 2x
<=> 4x2 - 4x + 5 - 4x2 + 3x - 1 + 2x = 0
<=> x + 4 = 0
<=> x = -4
4) ( x + 3 ) ( 2x + 1 ) - 2x2 = 4x - 5
<=> 2x2 + x + 6x + 3 - 2x2 - 4x + 5 = 0
<=> 3x + 8 = 0
<=> 3x = -8
<=> x = -8/3
5) -4 ( 2x - 8 ) + ( 2x - 1 )( 4x + 3 ) = 0
<=> - 8x + 32 + 8x2 + 6x - 4x - 3 = 0
.......
6) -3 . (x-2) + 4 . (2x-6) - 7 . (x-9)= 5 . (3-2)
<=> -3x + 6 + 8x - 24 - 7x + 63 - 5 = 0
<=> -2x + 40 = 0
<=> -2x = -40
<=> x = 20
Còn lại tương tự ....
Tìm x, biết:
a) (4x - 1)(x + 2) - 7x = (2x - 1)(3 + 2x)
b) (6x + 7)(2x - 3) - (3x - 5)(4x + 1) = 8
c) (x - 1)(x + 1) - (x - 2)(x + 4) = 10\(\)
d) (3x + 2)(x - 5) = 3(x + 1)^2 - 2
e) 5x(x - 3) = x - 3
1. Tìm x, biết rằng:
a, ( x+3 )( x + 1) - x ( x - 5 ) = 11
b, ( 8x + 2 )( 1 - 3x ) + ( 6x - 1 )( 4x - 10 ) = -50
a) \(\left(x+3\right)\left(x+1\right)-x\left(x-5\right)=11\)
\(\Leftrightarrow x^2+x+3x+3-x^2+5x=11\)
\(\Leftrightarrow9x+3=11\)
\(\Leftrightarrow9x=11-3\)
\(\Leftrightarrow9x=8\)
\(\Leftrightarrow x=\dfrac{8}{9}\)
b) \(\left(8x+2\right)\left(1-3x\right)+\left(6x-1\right)\left(4x-10\right)=-50\)
\(\Leftrightarrow\left(8x-24x^2+2-6x\right)+\left(24x^2-60x-4x+10\right)=-50\)
\(\Leftrightarrow2x-24x^2+2+24x^2-64x+10=-50\)
\(\Leftrightarrow-62x+12=-50\)
\(\Leftrightarrow-62x=-50-12\)
\(\Leftrightarrow-62x=-62\)
\(\Leftrightarrow x=\dfrac{-62}{-62}\)
\(\Leftrightarrow x=1\)
a) \(\left(x+3\right)\left(x+1\right)-x\left(x-5\right)=11\)
\(x^2+x+3x+3-x^2+5x=11\)
\(x+8x+3=11\)
\(x+8x=8\)
\(x\left(8+1\right)=8\)
\(x=\dfrac{8}{9}\)
b) \(\left(8x+2\right)\left(1-3x\right)+\left(6x-1\right)\left(4x-10\right)=-50\)
\(8x-24x^2+2-6x+24x^2-60x-4x+10=-50\)
\(-62x+12=-50\)
\(-62x=-62\)
\(x=1\)
Tìm x biết
a,|x-1|+2x=3
b,|x+1|+|x+3|=10-4x
c,|x+1++3|x-2|-5|4-x|=13-2x
d,3|x-2|-2.|x+5|+4.|x-1|=9-7x
a,x=\(\frac{4}{3}\)
b, x= 1
c, x= viết đề rõ hơn
d, \(\frac{13}{6}\)