Question

36x+45y=123 46x+15y=23

Answer 1

Elimination Method

$\left\{\begin{array}{ccc}36x+45y=123&\text{divide both sides by (-3)}\\46x+15y=23\end{array}\right\\\\\underline{+\left\{\begin{array}{ccc}-12x-15y=-41\\46x+15y=23\end{array}\right}\qquad\text{add both sides of the equations}\\.\qquad\qquad34x=-18\qquad\text{divide both sides by 34}\\.\qquad\qquad x=-\dfrac{18}{34}\to\boxed{x=-\dfrac{9}{17}}\\\\\text{Put the value of x to the second equation.}\\\\46\left(-\dfrac{9}{17}\right)+15y=23$

$-\dfrac{414}{17}+15y=\dfrac{391}{17}\qquad\text{add}\ \dfrac{414}{17}\ \text{to both sides}\\\\15y=\dfrac{805}{17}\qquad\text{divide both sides by}\ 15\\\\y=\dfrac{805}{255}\\\\\boxed{y=\dfrac{161}{51}}\\\\Answer:\ \boxed{x=-\dfrac{9}{17}\ and\ y=\dfrac{161}{51}}$