Question

Consider the following linear system.

-2x+5y=23
-10x+ky=115
The value of k that will produce a system with an infinite number of solutions is:
a. -25
b. 25
c. -5
d. 5

Answer 1

b. 25

Explanation:

To have an infinite number of solutions, both equations must be equal.

-2x + 5y = 23

-10x + ky = 115

Multiply both sides of the first equation by 5 and write it. Rewrite the second equation below the first equation.

-10x + 25y = 115

-10x + ky = 115

For the equations to be equal, you must have

25y = ky

Divide both sides by y.

k = 25

Answer: b. 25