Mathematics
Solve the following systems of simultaneous linear equations by the elimination method
15x - 14y = 117
14x - 15y = 115
Answer
Given,
15x - 14y = 117 …….(i)
14x - 15y = 115 …….(ii)
Multiplying eq. (i) by 14 and eq. (ii) by 15 we get,
210x - 196y = 1638 …….(iii)
210x - 225y = 1725 …….(iv)
Subtracting eq. (iii) from (iv) we get,
⇒ 210x - 225y - (210x - 196y) = 1725 - 1638
⇒ 210x - 210x - 225y + 196y = 87
⇒ -29y = 87
⇒ y = -3.
Substituting value of y in eq. (ii) we get,
⇒ 14x - 15(-3) = 115
⇒ 14x + 45 = 115
⇒ 14x = 115 - 45
⇒ 14x = 70
⇒ x = 5.
Hence, x = 5 and y = -3.