How many solutions does this linear system have?

y = 2x – 5

–8x – 4y = –20

a. one solution: (–2.5, 0)
b. one solution: (2.5, 0)
c. no solution
d. infinite number of solutions

Respuesta :

B. One solution: (2.5, 0)

Substitute the first equation to the second equation to find for X:
-8X - 4 (2X - 5) = -20.
Multiplying 4 (2X - 5) will give you (8X - 20).

The equation will now be:
-8X - (8X - 20) = -20 or -8X - 8X +20 = -20
-16X = -20 -20
-16X = -40
X = 2.5


To get Y, substitute the answer that we got from X to the first equation:
Y = 2 (2.5) - 5
Y = 5 - 5
Y = 0

The linear system of equation have one solution and the ordered pair are (2.5, 0)

How to find the solution to a linear system?

y = 2x - 5

-8x - 4y = -20

substitute the value of y in equation(ii)

Therefore,

-8x - 4(2x - 5) = -20

-8x - 8x + 20 = -20

-16x = -40

x = -40 / -16

x = 2.5

Hence,

y = 2(2.5) - 5

y = 5 - 5

y = 0

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