Question

How many pairs (x, y) satisfy the equations 3x +5y =21 and 4x +7y =29 ?

Answer 1

here a1=3
a2=4
b1=5
b2=7
a1/a2 is not equal to b1/b2
therefore consistent and having an unique solution.

Answer 2

( 3 x + 5 y= 21 )4 =12 x+ 20y = 84

( 4 x +7 y= 29 )3=12 x + 21 y= 87 therefore we eliminate x by subtraction.

y = 3

x = 2.therefore (2, 3) (x, y)

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