Rozwiąż równanie: a) [latex]-7 x^{2} + 42x=0[/latex] b) [latex]36 x^{2} = 6x[/latex] c) [latex] x^{2} +10x + 25=0[/latex]

[latex]a) \ -7x^2+42x=0 \ -7x(x-6)=0 \ -7x=0 lor x-6=0 \ x=0 lor x=6 \ oxed{x in { 0, 6 } } \ \ b) \ 36x^2=6x \ 36x^2-6x=0 \ 6x(6x-1)=0 \ 6x=0 lor 6x-1=0 \ x=0 lor 6x=1 \ x=0 lor x=frac{1}{6} \ oxed{x in { 0, frac{1}{6} }} \ \ c) \ x^2+10x+25=0 \ x^2+2 cdot 5 cdot x + 5^2=0 \ (x+5)^2=0 \ x+5=0 \ oxed{x=-5}[/latex]