How many solutions does the system have? { y = -2x + 4 { 7y = -14x + 28 Choose 1 answer: A. Exactly one solution B. No solutions C. Infinitely many solutions

Mathematics · Middle School · Mon Jan 18 2021

Answered on

Solve equation [2] for the variable  y  

 

 7y = 7x + 28

 y = x + 4

Plug this in for variable  y  in equation [1]

-8x + 4•(x +4) = 24

-4x = 8

Solve equation [1] for the variable  x  

4x = - 8  

x = - 2

By now we know this much :

  x = -2

  y = x+4

Use the  x  value to solve for  y  

  y = (-2)+4 = 2

Solution :

{x,y} = {-2,2}

and this intersects at only one point so your answer is A