a: =>5x+35-12=3x-3+11
=>5x+23=3x+8
=>2x=-15
hay x=-15/2
b: \(\Leftrightarrow25-6x^2+15x=6x^2+6x-17\)
=>\(-6x^2+15x+25-6x^2-6x+17=0\)
=>\(-12x^2+9x+42=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{3+\sqrt{233}}{8}\\x=\dfrac{3-\sqrt{233}}{8}\end{matrix}\right.\)
Giúp mình với huhu:(

G
