y=3x and 2x-15y=86

Question

Solve using the substitution method

Answer 1

2x - 15y = 86 ----eq1

           ↑

   y = 3x ----eq2

we can substitute in eq1  instead of y, we put 3x

 

2x - 15*(3x) = 86----> 2x - 45x = 86 ----> -43x=86 -----> divide both side by -43 we get 

x =-2 then we substitute this value in eq2 to find y 

y = 3 * (-2) -----> y =-6

 

Best