Question

Calculati-l pe x: 1)(x-3)²+7=2x+(x+4)². 2)1+x(x-1)=(x-2)². 3)(x-3)²+2(x+5)(x-5)=3·(x+1)²+4. 4)12-2(x-1)²=4(x-2)-(x-3)(2x-5).

Answer 1

1) x²-6x+9+7=2x+x²+8x+16⇒x²-x²-6x-10x=16-16⇒-16x=0⇒x=0
2)1+x²-x=x²-4x+4⇒x²-x²-x+4x=4-1⇒3x=3⇒x=1;
3)x²-6x+9+2(x²-25)=3(x²+2x+1)+4⇒x²-6x+9+2x²-50=3x²+6x+3+4⇒        3x²-3x²-6x-6x=7+50-9⇒-12x=48⇒x=4;
4)12-2(x²-2x+1)=4x-8-(2x²-5x-6x+15)⇒12-2x²+4x-2=4x-8-2x²+5x+6x-15⇒
-2x²+2x²+4x-4x-11x=-23+2-12⇒-11x=-33⇒x=3 :-)