Find the value of x + y, if 15x + 17y = 85 and 17x + 15y=75

1.	Find the value of x + y, if 15x + 17y = 85 and 17x + 15y=75
Answer» 15x + 17y = 85.....(1)17x + 15y = 75.....(2) Multiply eq(1) by 17 and eq(2) by 15 1517x + 1717y = 85171715x + 1515y = 7515 Subtract these equations (1717 - 1515)x = 1445 - 1125(289 - 225)x = 32064x = 320x = 320/64 = 5 Put value of x = 5 in eq(1) 15*5 + 17y = 8517y = 85-75y = 10/17 X + Y = 5 + 10/17 = 95/17

Answer»

15x + 17y = 85.....(1)17x + 15y = 75.....(2)

Multiply eq(1) by 17 and eq(2) by 15

15*17x + 17*17y = 85*1717*15x + 15*15y = 75*15

Subtract these equations

(17*17 - 15*15)x = 1445 - 1125(289 - 225)x = 32064x = 320x = 320/64 = 5

Put value of x = 5 in eq(1)

15*5 + 17y = 8517y = 85-75y = 10/17

X + Y = 5 + 10/17 = 95/17

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