Question

78x+91y=39 and 65x+117y=42 by elimination method

Answer 1

78x+91y=39 ----- (i)
65x+117y=42 ---- (ii)

Multiply (i) by 65 and (ii) by 78

5070x + 5915y = 2535 ---- (iii)
5070x + 9126y = 3276 ---- (iv)

Subtract (iv) from (iii)

-3211y = -741

y = -741/-3211

y = 3/13

78x+91y=39 ----- (i)

78x+91(3/13) =39

78x + 21 = 39

78x = 18

x = 18/78

x = 3/13

x = 3/13 and y = 3/13

Answer 2

heya...!!!!


78x + 91y = 39------(1)
65x + 117y = 42------(2)


multiply --(1) by 65 and --(2) by 78

5070x + 5915y = 2535
5070x + 9126y = 3276
(-)_____(-)______(-)
————————————
-3211y = - 741

=> y = -741/-3211

=> y = 3/13 put in--(1)

we get,

78x + 91(3/13) = 39

=> 78x + 21 = 39

=> 78x = 39 - 21

=> x = 18/78

=> x = 3/13