[tex]\displaystyle a).3 \sqrt{2} x+7=0 \\ 3 \sqrt{2} x=0-7 \\ 3 \sqrt{2} x=-7 \\ x=- \frac{7}{3 \sqrt{2} } \\ x=- \frac{7 \sqrt{2} }{6} \\ b).16x-3(x+1)=5x \\ 16x-3x-3=5x \\ 16x-3x-5x=3 \\ 8x=3 \\ x= \frac{3}{8} [/tex]
[tex]\displaystyle c).2,5(x-4)-6x=3-x \\ 2,5x-10-6x=3-x \\ 2,5x-6x+x=3+10 \\ -2,5x=13 \\ x=- \frac{13}{2,5} \\ x=-5,2[/tex]