$4\left(3x+5\right)-3\left(2x-1\right)=5$

$a^{2}c-b^{2}c-a^{2}+b^{2}$

$\begin{cases} 3(x+2)-2y=18 \\ \frac{2}{5}x+\frac{7}{15}y=-\frac{3}{5}\end{cases}$

$x^{2}-6x=7$

$\frac{\sqrt{15}}{\sqrt{8}}\div \frac{\sqrt{5}}{2\sqrt{2}}\times(-\sqrt{30})$

$\lim_{x\to1}(\frac{x^{2}+2x-3}{x-1})$

$2(2x+1)-6(x+3)\leq0$

$y=x^{2}-2x-48$

$\int(3x^{2}-4x+5)dx$