Question

If a = -12/5, then 5x + 2y = 6 and 3x - ay = 4 are parallel. please help!! true or false.

Answer 1

3x - ay = 4
3x - (-12/5)y = 4
3x + 12/5y = 4 -- multiply by the LCD, which is 5, to get rid of the fraction
15x + 12y = 20

now we have :
15x + 12y = 20
12y = -15x + 20
y = -15/12x + 20/12
y = - 3/4x + 5/3 (slope here is -3/4)

5x + 2y = 6
2y = -5x + 6
y = -5/2x + 3 (slope here is -5/2)
since the slopes are not the same, these lines are not parallel

Answer 2

wait...I made a mistake...hold on

Answer 3

15x + 12y = 20
12y = -15x + 20
y = -15/12x + 20/12
y = - 5/4x + 5/3

it didn't change the answer...NOT PARALLEL because the slope of 1 is -5/4 and the slope of the other is -5/2