25-x2=21 2x2+3=3-7x (6x+3)(9-x)=0 4x+2/3=2x-1 x(x-1)=5x

25-x²=21 x²=25-21 x²=4 x=-2 x=2 2x2+3=3-7x 2x²+7x=0 x(2x+7)=0 x=0  x=-3,5 (6x+3)(9-x)=0 x=-0,5  x=9 4x+2/3=2x-1 4x-2x=-2/3-1 2x=-1 2/3 x=-1 2/3:2=5/3*1/2=5/6 ---------------------------------------- (4x+2)/3=2x-1 4x-6x=-3-2= -2x=-5 x=2,5 x(x-1)=5x x²-x-5x=0 x(x-6)=0 x=0  x=6

[latex]25-x^2=21\to -x^2=21-25=-4\ \textless \ =\ \textgreater \ x^2=4\\x=б2[/latex] Ответ: [latex]б2[/latex] [latex]2x^2+3=3-7x\ \textless \ =\ \textgreater \ 2x^2+7x=0\ \textless \ =\ \textgreater \ x(2x+7)=0[/latex] [latex]x=0[/latex] или [latex]2x+7=0\to x=-\frac{7}{2}=-3,5[/latex] Ответ: [latex]0;-3,5[/latex] [latex](6x+3)(9-x)=0[/latex] [latex]6x+3=0\to x=-\frac{1}{2}=-0,5[/latex] или [latex]9-x=0\to x=9[/latex] Ответ: [latex]9;-0,5[/latex] [latex]4x+\frac{2}{3}=2x-1\\2x=-1\frac{2}{3}=-\frac{5}{3}\to x=-\frac{5}{6}[/latex] Ответ: [latex]-\frac{5}{6}[/latex] [latex]x(x-1)=5x\ \textless \ =\ \textgreater \ x^2-x=5x\to x(x-6)=0[/latex] [latex]x=0[/latex] или [latex]x-6=0\to x=6[/latex] Ответ: [latex]0;6[/latex]