Question

tìm x biết

a) \(\left(2x-1\right)^2+\left(x+3\right)^2-5\left(x+7\right)\left(x-7\right)=24\)

b) \(\left(x+3\right)^2-\left(x-4\right)\left(x-8\right)=1\)

Answer 1

a ) \(\left(2x-1\right)^2+\left(x+3\right)^2-5\left(x+7\right)\left(x-7\right)=24\)

\(\Leftrightarrow4x^2-4x+1+x^2+6x+9-5x^2+245=24\)

\(\Leftrightarrow2x=-231\Leftrightarrow x=\dfrac{-231}{2}\)

b ) \(\left(x+3\right)^2-\left(x-4\right)\left(x-8\right)=1\)

\(\Leftrightarrow x^2+6x+9-x^2+12x-32=1\)

\(\Leftrightarrow18x=24\Leftrightarrow x=\dfrac{4}{3}\)

Chúc bạn học tốt !!!!!!!!!!!!