a)x+(3x+1)+3=7 b)3x(x+2)-5x=3 c) x-3+2x+4=x+4 d)2(x+4)-5=-7

a)x+(3x+1)+3=7 x+3x+1+3=7 4x=7-1-3 4x=3 x=3/4 b)3x(x+2)-5x=3 3x²+6x-5x=3 3x²+x-3=0 Δ=1-4*3*(-3)=1+36=37 √Δ=√37 x₁=(1-√37)/6 x₂=(1+√37)/6 c) x-3+2x+4=x+4 3x+1-x-4=0 2x=3 x=3/2 d)2(x+4)-5=-7 2x+8-5=-7 2x=-10 x=-5