if the points A(3,5) and B(1,4) lie on the graph of the line ax+by=7.find the values of A and B?
For the points A (3, 5) and B (1, 4) to lie on the graph of line ax + by = 7 must satisfy the given equation
So for x = 3 and y = 5
3a + 5b = 7 .................(1)
for x =1 and y = 4
a + 4b = 7
⇒ a = 7 – 4b ................(2)
putting the value of a from (2) in (1) we get
3(7 – 4b) + 5b = 7
21 – 12b + 5b = 7
–7b = 7 – 21 = – 14
Putting the value of b in (2) we get
a = 7 – 4 × 2 = – 1
Hence the values of a and b are – 1 and 2