Question

ax+2y=5
3x-6y=20
In the system of equations above, a is a constant.
If the system has one solution, which of the following can NOT be the value of a? Explain.
A) -1
B) $\frac{3}{4}$
C) 1
D) 3

Answer 1

answer

the 3 & 1 can not be the value of a

explanation

a1/a2= a/3

b1/b2=2/-6

c1/c2=5/20

a1/a2=b1/b2 = a/3 = 2/-6

= -6a=6

=. a=6/-6

= a=1

a1/a2 = b1/b2 = a/3 = 5/20

=. 20a= 15

=. a= 15/20

=. a= 3/4

: the 1and3 can't be the value of a