Medal will be given :D

4x - 3y = k

-8x + 6y = 10
If the pair of equations has infinitely many solutions, what is the value of k?

A)-10
B)-5
C)5
D)10

Question

Medal will be given :D

4x - 3y = k

-8x + 6y = 10
  If the pair of equations has infinitely many solutions, what is the value of k?

A)-10	
B)-5	
C)5	
D)10

anonymous · Answer

Lets start by just leaving k in there and trying to combine the two equations to solve.
Can you see an easy way to combine the 2 equations into 1?

rissyroo118 · Answer

i multiple , but i'd say k=10/-2=-5 so the answer i come up with is B

anonymous · Answer

right so (i think) the easiest way is to add 2 times the first equation to the second equation:
2*4x-2*3y+(-8x+6y)=2*k+10
left hand side goes to zero, 2k+10=0
k=-5
you're absolutely right!