C

tìm x biết:

\(x^2 -9^2=25^2 -x^2-16^2\)

B. No, there isn’t.

tính giá trị biểu thức sau:

\(A= \dfrac { 2^{19} . 27^3 - 15 . 4^9 . 9^4 }{ 6^9 . 2^{10} + 12^ {10}}\)

tối giản biểu thức sau:

a)f(x,y)=\(( \dfrac 1 3 .x+2y)( \dfrac 1 9 x^2 - \dfrac 2 3 xy + 4y^2)\)

b)f(x)=\((x^2-\dfrac 13)(x^4+\dfrac 13x^2+\dfrac 19)\)

( sử dụng các hằng đẳng thức đáng nhớ)

c)(x+4)\(^2\)-64=0

=>(x+4)\(^2\)=64

=>(x+4)\(^2\)=8\(^2\)

=>x+4=8

=>x=4

d)(x+13)\(^3\)+27=0

(x+13)\(^3\)=-27

(x+13)\(^3\)=(-3)\(^3\)

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