Question

Help!!

How many solutions does this system have?

y = 3/4x - 5
3x+ 4 y= -20
one
two
an infinite number
no solution

Answer 1

A) one

Explanation:

y = 3/4x - 5

3x+ 4 y= -20

3x + 4(3x/4 - 5) = -20

3x + 3x - 20 = -20

6x = 0

x = 0

y = -5

One solution: (0,-5)

Answer 2

one solution

Explanation:

y = 3/4x - 5

3x+ 4 y= -20

Substitute the first equation into the second equation

3x+ 4 (3/4x -5)= -20

Distribute

3x +3x - 20 = -20

6x -20 = -20

Add 20 to each side

6x -20+20 = -20+20

6x = 0

x=0

We need to find y

y = 3/4x -5

y =0-5

y = -5

There is one solution