Question

For which values of a and b does the following pair of linear equations have an infinite number of solutions? 2x+3y=7; (a-b)x+(a+b)y=3a+b-2

Answer 1

2/( a-b) = 3/( a+b) = 7/ ( 3a+b-2)

2a + 2b = 3a - 3b
-a = -5b
a = 5b

9a + 3b -6 =7 a + 7b

2a -4b = 6

put a = 5b

10 b - 4b = 6
b = 1

a = 5