Question

If the 2 lines given by the equations 12x+3y=20 and ax+y=10 don't intersect when graphed, what is the value of "a"?

Answer 1

if they don't intersect, it means they're parallel and their gradient is the same. find the gradient of the first equation and that's equal to "a" :)

Answer 2

set both equal to y, and make them have the same slope

Answer 3

as long as they dont have the same y intercept they will not cross if they have the same slope

Answer 4

3y = 20 -3x

y = -x-(20/3)

and the other equation set to y is what?

Answer 5

@mitchelsewbaran ?

Answer 6

hmmm.....

Answer 7

that should be +(20/3)

Answer 8

y = -x+(20/3)

Answer 9

solve for y in the second equation

Answer 10

y = -ax+10

we want them to have the same slope so what does a need to be?
y = -x+(20/3)
y = -ax+10

a = ?

Answer 11

10?

Answer 12

12x+3y=20
solve for y
3y=-12x+20
y=-4x+(20/3)
can u tell what the slope is?

Answer 13

@mitchelsewbaran ... ?

Answer 14

hold on