In: Math
Solve the simultaneous equations:
a) x + y = 7, 3x - 2y = 11
b) 7x - 2y = 1, 3x + 4y = 15
Solution:
a) We have:
x + y = 7
or, y = 7 - x - Eq. I
3x - 2y = 11 - Eq. II
Substitute value of y from Eq. I in Eq. II:
3x - 2 (7 - x) = 11
⇒ 3x - 14 + 2x = 11
⇒ 5x = 11 + 14 = 25
⇒ x = 25/5 = 5
Substitute x = 5 in Eq. I:
y = 7 - 5 =3
Thus, the solution of given equations is: x = 5, y = 2
a) We have:
7x - 2y = 1 - Eq. I
3x + 4y = 15 - Eq. II
Multiplying Eq. I by 2:
14x - 4y = 2 - Eq. III
Adding Eq. II and Eq. III:
17x = 17
⇒ x = 17/17 = 1
Substitute x = 1 in Eq. I:
7 (1)- 2y = 1
⇒ 7 - 1 = 2y
⇒ y = 6/2
Thus, the solution of given equations is: x = 1, y = 3
Thus, the solution of given equations is: a) x = 5, y = 2 and b) x = 1, y = 3