Question

From the given pair of linear equations 3x+ay=50 and 9x-21y=15.Find the value of 'a' for them to be parallel

Answer 1

Answer:

a=-7

explanation

see in the attachment provided above......

Answer 2

Answer:

slope m = -a/b

equations

3x+ay-50=0 ......(1)

9x-21y-15=0 ......(2)

eq(1)

a=3 b=a

slope m1=-a/b

=-3/a

eq(2)

a=9 b=-21

slope m2=-a/b

=-9/-21

=3/7

from eq (1) and (2) (for parallel m1=m2)

-3/a=3/7

3a=-21

a= -7