b) Ta có :
\(VT=\left(4x-3y+2\right)-\left(3x-4y+2\right)\)
\(=4x-3y+2-3x+4y-2\)
\(=\left(4x-3x\right)-\left(3y-4y\right)+\left(2-2\right)\)
\(=x+y\)
\(VP=\left(2x+2y\right)-\left(x+y\right)=2x+2y-x-y\)
\(=\left(2x-x\right)+\left(2y-y\right)\)
\(=x+y\)
\(\Rightarrow VT=VP\)
\(\Rightarrow\)đpcm
Bài 1: Phá dấu ngoặc rồi tính:
a)\(\left(a+b+c\right)-\left(a-b+c\right)\)
b)\(\left(4.x+5.y\right)-\left(5.x-4.y-1\right)\)
Bài 2: Chứng minh bất đẳng thức:
a)\(\left(a+b+c+d\right)-\left(a-b-c+d\right)+1=a-\left(a-2b-2c-d\right)+\left(d+1\right)\)
b)\(\left(4x-3y+2\right)-\left(3x-4y+2\right)=\left(2x+2y\right)-\left(x+y\right)\)
Chứng minh rằng :
a)\(\dfrac{1}{x}\)-\(\dfrac{1}{x+a}=\dfrac{a}{x\left(x+a\right)}\)
b)\(\dfrac{1}{x\left(x+1\right)}-\dfrac{1}{\left(x+1\right)\left(x+2\right)}=\dfrac{2}{x\left(x+1\right)\left(x+2\right)}\)
c)\(\dfrac{1}{x\left(x+1\right)\left(x+2\right)}-\dfrac{1}{\left(x+1\right)\left(x+2\right)\left(x+3\right)}=\dfrac{3}{x\left(x+1\right)\left(x+2\right)\left(x+3\right)}\)
Tìm STN x biết rằng:
a)\(720:[41-\left(2x-5\right)]=2^3\cdot5\)
b)\(\left(x+1\right)+\left(x+2\right)+\left(x+3\right)+...+\left(x+100\right)=5+50\)
d)\(\left(x+3\right)^{10}=\left(x-3\right)^{17}\)
Tìm x:
a,\(x^2\) - 9 = 0
b,\(\left(x-3\right)^2-25=0\)
c,\(\left(x-3\right)\left(2x-5\right)=0\)
d,\(\left(x-3\right)\cdot x-2\left(x-3\right)=0\)
e,\(3x\left(x-1\right)-5\left(1-x\right)=0\)
g,\(x^2+6x-7=0\)
h,\(2x^2+5x-7=0\)
1.Tìm x,y
a)\(\left|x\right|\)=2017
b)\(\left|x\right|\)=\(\left|2017\right|\)
c)\(\left|x\right|\)+\(\left|y\right|\)=0
d)\(\left|x+5\right|\)+\(\left|y-3\right|\)=0
f)\(\left|x+2\right|\)=\(-5\)
Tìm x , y biết
a) 3x+2\(⋮\) 2x-1
b) x2-2x+3\(⋮\)x-1
c) \(|2x-3|+\left(y-1\right)^{2^{ }}+\left(27-1\right)^2\le0\)
Tính giá trị của các biểu thức
A =5a3b4 với a=-1;b=1
B=9a5b2với a=1;b=-1
C= ax+bx+ay+by với \(\left\{{}\begin{matrix}a+b=-2\\x+y=17\end{matrix}\right.\)
Tìm Max ; Min
A=\(|x-3|+1\)
B=\(3-|x+1|\)
C=\(\left(x-1\right)^2+\left|2y+2\right|.3\)
Bài 1; Tìm x, biết:
a) \(\text{2. |4 - x| = |-8|}\)
b) \(\left(x-1^2\right)=0\)
c) \(x\left(x-1\right)=0\)
d) \(\left(x+1\right)\left(x-2\right)=0\)
Tìm x
a, \(311-x+82=46+\left(x-21\right)\)
b,\(-\left(x-3+85\right)=\left(x+70-71\right)-5\)
c,\(-2\left(x+6\right)+6\left(x-10\right)=8\)
d,\(\left|x\right|=41\)
e, \(\left|-8\right|.\left|x\right|=\left|-56\right|\)
f,\(3.\left|x-2\right|+2x=19\) với \(x\) \(\ge\) 2
Giúp hộ đi ạ, cảm ơn.
