Question

If 2a-3b=1 and 5a+2b=50, then what is the value a-b

Answer 1

Solution :

2a - 3b = 1 ---( 1 )

5a + 2b = 50 ---( 2 )

Multiply equation ( 1 ) by 2 , and

equation ( 2 ) by 3 , we get

4a - 6b = 2 ---( 3 )

15a + 6b = 150 ---( 4 )

Add ( 1 ) and ( 2 ), we get

19a = 152

=> a = 152/19

=> a = 8

Substitute a = 8 in equation ( 1 ), we

get

2×8 - 3b = 1

=> 16 - 3b = 1

=> -3b = 1 - 16

=> -3b = -15

=> b = ( -15 )/( -3 )

=> b = 5

Therefore ,

a - b = 8 - 5 = 3

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