Question

a+9b=19

a+2b=-2

Answer 1

a+9b=19 ; a=19-9b--->eq 1

a+2b=-2 --->eq 2
subs eq1 into eq 2
19-9b+2b=-2
19-7b=-2
19+2=7b
21/7=b
b=3
subs b=3 into eq 1
a=19-9(3)
a=19-27
a=-8