Find the value of y in the solution to the system of equations shown.
3y = 18x + 6
y = 2x + 14

A. y = 3
B. y = 4
C. y = 20
D. y = 26

Respuesta :

  • 3y=18x+6

Divide by 3

  • y=6x+2--(1)
  • y=2x+14--(2)

Equating

  • 6x+2=2x+14
  • 4x=12
  • x=3

Now

  • y=6(3)+2
  • y=18+2
  • y=20

C

Answer:

C.  y = 20

Step-by-step explanation:

Given system of equations:

[tex]\begin{cases}3y = 18x + 6\\y = 2x + 14\end{cases}[/tex]

Multiply the second equation by 3:

[tex]\implies (3)y=(3)2x+(3)14[/tex]

[tex]\implies 3y=6x+42[/tex]

Subtract this from the first equation to eliminate 3y:

[tex]\begin{array}{r l}3y & = 18x+6\\-\quad3y&=6x+42\\\cline{1-2}0&=12x-36\end{array}[/tex]

Solve the resulting equation for x:

[tex]\implies 12x-36=0[/tex]

[tex]\implies 12x=36[/tex]

[tex]\implies x=3[/tex]

Substitute the found value of x into the original second equation and solve for y:

[tex]\implies y=2(3)+14[/tex]

[tex]\implies y=6+14[/tex]

[tex]\implies y=20[/tex]