Question

If the point A(3,5) and B(1,4) lies on the graph of line ax+by =7 , find the value of a??

Please answer this

Answer 1

Answer:

a=1 and b=3/2

Step-by-step explanation:

let ax+by=7 ------- (1)

at point A(3,5) put x=3 y=5 in eq (1)

we get

a(3)+b(5)=7

=> 3a+5b=7 ------ (2)

at point B(1,4) put x=1 y=4

we get

a(1)+b(4)=7

=> a+4b=7 ------ (3)

now eq (3)× 3 we get

3a+12b = 21 ----- (4)

solving eq (2) - eq (4)

we get

3a +5b =7

3a+12b =21

- - -

--------------------

0 - 7b = -14

=> b = 2

putting b=2 in eq (3)

a+4(2)=7

a +8 = 7

a = -1