Question

pls answer this question...​

Answer 1

if A ( 3,5) and B(1,4) are solutions of equation ax +by = 7

Then ..

3a +5b = 7

=> a = (7-5b)/3 ...(1)

a +4b = 7

=> a = 7-4b ...(2)

From (1) and (2)

(7-5b)/3 = 7-4b

=> 7-5b = 21 -12 b

=> 7b = 14

=> b = 2 ...(3)

From (3) and (2)

7-4×2 = a

=> a = 7-8 = -1

=> a = -1