Please help me to solve these equations:
3x - 4 = x + 5
X x 3X = x2 + 4
$\displaystyle 3x-x = 5+4$
$\displaystyle 2x=9$
$\displaystyle x=\frac{9}{2}$
lets check it.
$\displaystyle 3 * \frac{9}{2} - 4 = \frac{9}{2} + 5$
$\displaystyle \frac{27}{2} - \frac{8}{2} = \frac{9}{2} +\frac{10}{2}$
$\displaystyle \frac{19}{2}= \frac{19}{2}$
i assume that this is your equation. $\displaystyle x*3x = x^2 +4$X x 3X = x2 + 4
$\displaystyle 3x^2= x^2 +4$
$\displaystyle 3x^2-x^2 = 4$
$\displaystyle 2x^2=4$
$\displaystyle \sqrt{2x^2}=\sqrt{4}$
$\displaystyle x\sqrt{2}=2$
$\displaystyle x=\frac{2}{\sqrt{2}}$
$\displaystyle
x=\frac{2}{\sqrt{2}}*\frac{\sqrt{2}}{\sqrt{2}}
$
$\displaystyle x=\frac{2\sqrt{2}}{2}$
$\displaystyle x=\sqrt{2}$
$\displaystyle \sqrt{2}*\sqrt{2}^2= \sqrt{2}^2 + 4$
$\displaystyle 4+2= 2+4$
$\displaystyle 6=6$