$$ \begin{aligned} 90 &= 15x-43+8x+18&& \text{simplify right side} \\[1 em]90 &= 23x-25&& \text{ swap the left and right side of the equation } \\[1 em]23x-25 &= 90&& \text{ move -25 to the right } \\[1 em]23x &= 90+25&& \\[1 em]23x &= 115&& \text{ divide both sides by $ 23 $ } \\[1 em]x &= \frac{115}{23}&& \\[1 em]x &= 5&& \\[1 em] \end{aligned} $$

This page was created using