Question

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

Answer 1

c

Explanation:

khan

Answer 2

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

Explanation:

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