Question

Tìm x,y biết :

a,x⁴-x³-7x²+x+6=0

b,(x+y)²+(1+x)(1+y)=0

c,2x²+2xy+y²+9=6x-|y+3|

Answer 1

I don't now

or no I don't

..................

sorry

Answer 2

a) \(x^4-x^3-7x^2+x+6=0\)

\(\Leftrightarrow\)\(x^4-x^3-7x^2+7x-6x+6=0\)

\(\Leftrightarrow\)\(x^3\left(x-1\right)-7x\left(x-1\right)-6\left(x-1\right)=0\)

\(\Leftrightarrow\)\(\left(x-1\right)\left(x^3-7x-6\right)=0\)

\(\Leftrightarrow\)\(\left(x-3\right)\left(x-1\right)\left(x+1\right)\left(x+2\right)=0\)

đến đây lm tiếp