\(what\) \(the\) \(abcd?\)
\(what\) \(the\) \(abcd?\)
1) Rút gọn biểu thức :
a)\(\frac{\left(a-b\right)\left(a-d\right)}{\left(b^2-a^2\right)\left(d^2-c^2\right)}\)
b)\(x^4-2x^2y+xy^2-9xy^4\)
c)\(x^3-2x^2y+xy^2-9xy^4\)
d)\(\left(ax+by\right)^2-\left(ay+bx\right)^2\)
Rút gọn biểu thức:
a) \(A=\left(x-y\right)^3+\left(y+x\right)^3+\left(y-x\right)^3-3xy\left(x+y\right)\)
b) \(B=3x^2\left(x+1\right)\left(x-1\right)-\left(x^2-1\right)\left(x^4+x^2+1\right)+\left(x^2-1\right)^3\)
c) \(C=\left(x+y\right)\left(x^2-xy+y^2\right)+\left(x-y\right)\left(x^2+xy+y^2\right)-2x^3\)
d) \(D=\left(x+1\right)^3+\left(x-1\right)^3+x^3-3x\left(x+1\right)\left(x-1\right)\)
Rút gọn biểu thức
a. Q= \(\left(x-y\right)^2\)-4(x-y)(x+2y)+4\(\left(x+2y\right)^2\)
b. A=\(\left(xy+2\right)^3\)-6\(\left(xy+2\right)^2\)+12(xy+2)-8
c. \(\left(x+2\right)^3\)+\(\left(x-2\right)^3\)-2x(\(x^2\)+12)
a) Cho \(x^2+y^2+z^2=xy+yz+zx\). CMR : x=y=z
b) cho \(\left(a-b\right)^2+\left(b-c\right)^2+\left(c-a\right)^2+4\left(ab+ac+bc\right)=4\left(a^2+b^2+c^2\right)\). CMR : a=b=c
Bài 3. Chứng minh các đẳng thức sau:
a. \(\left(x-y\right)\left(x^4+x^3y+x^2y^2+xy^3+y^4\right)=x^5-y^5\)
b. \(\left(x+y\right)\left(x^4-x^3y+x^2y^2-xy^3+y^4\right)=x^5+y^5\)
c. \(\left(a+b\right)\left(a^3-a^2b+ab^2-b^3\right)=a^4-b^4\)
đ. \(\left(a+b\right)\left(a^2-ab+b^2\right)=a^3-b^3\)
Chứng minh rằng:
a) \(\left(a^2-b^2\right)\left(c^2-d^2\right)=\left(ac+bd\right)^2-\left(ad+bc\right)^2\)
b) Nếu \(x^2+y^2+z^2=xy+xz+yz\) thì x=y=z
1,\(\left(x+3\right)^2-\left(2x-5\right)\left(x+3\right)\)
2,\(x^2-xy+x-y\)
3,\(x^3+6x^2+9x\)
4,\(x^2y+xy+x+1\)
5,\(ax+by+ay+bx\)
6,\(x^2-\left(a+b\right)x+ab\)
GIÚP MK VS
\(ab\left(x^2+y^2\right)-xy\left(a^2+b^2\right)\)
Chứng minh rằng các biểu thức sau bằng nhau
a. \(\left(a^2-b^2\right)\left(c^2-d^2\right)\)và \(\left(ac+bd\right)^2-\left(ad+bc\right)^2\)
b. Nếu \(x^2+y^2+z^2\) và \(xy+xz+yz\) thì x = y = z