$x+2y+10=0$

$y=2x^2-2x$

$2xh+x^2=50$

$W=-2p^2+690p-13000$

$y=0.5x-5$

$y=\frac{6}{x+2}$

$y=\pm \sqrt{4-x}$

$y=\pm \frac{2}{\sqrt{x}}$

$y=8-\frac{1}{3}x$

$y=2-x$

$y=\pm \sqrt{x^2-25}$

$y=\frac{25}{x}-\frac{1}{2}x$

$-2x^3-12x^2$

$\mathrm{-}{x}^2-8x$

$t^2+15t-100$

$3x^2-2x^2+3x-2$

$a^2-9$

$36x^2-36x+9$

$a^2-2+\frac{1}{a^2}$

$x^3-6x^2+12x-8$

$x(x-4)$

$-2t(t-9)$

$(x+6)(x-1)$

$\mathrm{-}(p+6)(p-2)$

$4(k-2)(k+2)$

$2p(p-4)(p+3)$

$(4-p)(4+p)$

$(x-9)(x-1)$

$\frac{3x+5y}{xy}$

$\frac{x+4}{x^2-2x}$

$\frac{2y}{3x}$

$\frac{4x^2-1}{2x}$

$A=2x^2$

$A=(x-6)(2x-10)$

$(x-6)(2x-10)=2x^2-2690$ gives $x=125$.