y = 9 x + 12 x + 7 y = 20 The solution to the given system of equations

Question

y = 9 x + 12 x + 7 y = 20 The solution to the given system of equations is x , y . What is the value of y ?

Accepted Answer

The correct answer is 3 . It&rsquo;s given that y = 9 x + 12 . Substituting 9 x + 12 for y in the second equation in the system, x + 7 y = 20 , yields x + 7 9 x + 12 = 20 , which gives x + 63 x + 84 = 20 , or 64 x + 84 = 20 . Subtracting 84 from each side of this equation yields 64 x = - 64 . Dividing each side of this equation by 64 yields x = - 1 . Substituting - 1 for x in the first equation in the system, y = 9 x + 12 , yields y = 9 - 1 + 12 , or y = 3 . Therefore, the value of y is 3 .

Question y-9-x-