Bỏ ngoặc, Ta có: a+b-c+a-b-a+b+c=a+a-a+b-b+b+c-c=a+b
P=a+b-c+a-b-a+b+c=a+b+(-c)+a+(-b)+(-a)+b+c=a+b
thế thôi
Rút gọn biểu thức :
\(A=\left(a+b-c\right)+\left(a-b\right)-\left(a-b\right)-\left(a-b-c\right)\)
Rút gọn các biểu thức sau :
a) \(A=\left(a-b\right)+\left(a+b-c\right)-\left(a-b-c\right)\)
b) \(B=\left(a-b\right)-\left(b-c\right)+\left(c-a\right)-\left(a-b-c\right)\)
c) \(C=\left(-a+b+c\right)-\left(a-b+c\right)-\left(-a+b-c\right)\)
Cho biểu thức
\(A=\left(-a-b+c\right)-\left(-a-b-c\right)\)
a) Rút gọn A
Bỏ dấu ngoặc rồi thu gọn biểu thức :
a, \(A=\left(a-2b+c\right)-\left(a-2b-c\right)\)
b, \(B=\left(-x-y+3\right)-\left(-x+2-y\right)\)
c, \(C=2.\left(3a+b-1\right)-3\left(2a+b-2\right)\)
Chứng minh các đẳng thức sau:
a) \(\left(a+b\right)-\left(-a+b-c\right)+\left(c-a-b\right)=a-b+2c\)+ 2c
b) \(a\left(b-c\right)-a\left(b+d\right)=-a\left(c+d\right)\)
Chứng minh đẳng thức:
a) \(\left(a+b\right)\left(c+d\right)-\left(a+d\right)\left(b+c\right)=\left(a-c\right)\left(d-b\right)\)
b) \(\left(a-c\right)\left(b+d\right)-\left(a-d\right)\left(b+c\right)=\left(a+b\right)\left(d-c\right)\)
Rút gọn các biểu thức sau :
a) \(A=\)\(\frac{4^5.9^4-2.6^9}{2^{10}.3^8+6^8.20}\)
b) \(B=\)\(\frac{\left(\frac{2}{3}\right)^3.\left(\frac{-3}{4}\right)^2.\left(-1\right)^5}{\left(\frac{2}{5}\right)^2.\left(\frac{-5}{12}\right)^3}\)
ĐƠN GIẢN CÁC BIỂU THỨC
\(a,-b-\left(b-a+c\right)\) \(b,-\left(a-b+c\right)-\left(c-a\right)\)
\(c,b-\left(b+a-c\right)\) \(d,a-\left(-b+a-c\right)\)
Chứng minh đẳng thức
a) \(\left(x-y\right)-\left(x-z\right)=\left(z+x\right)-\left(y+x\right)\)
b) \(\left(x-y+z\right)-\left(y+z-x\right)-\left(x-y\right)=\left(z-y\right)-\left(z-x\right)\)
c) \(a\left(b+c\right)-b\left(a-c\right)=\left(a+b\right)c\)
d) \(a\left(b-c\right)-a\left(b+d\right)=-a\left(c+d\right)\)
e) \(\left(a+b\right)\left(c+d\right)-\left(a+d\right)\left(b+c\right)=\left(a-c\right)\left(d-b\right)\)
f) \(\left(a-c\right)\left(b+d\right)-\left(a-d\right)\left(b+c\right)=\left(a+b\right)\left(d-c\right)\)
