Solve equations by using the substitution method.x + 2y = – 1 2x �

1.	Solve equations by using the substitution method.x + 2y = – 1 2x – 3y = 12
Answer» Given: x + 2y = -1 ……. (1) 2x – 3y = 12 …….. (2) From equation (1) x + 2y = -1 ⇒ x = – 1 – 2y Substituting x = – 1 – 2y in equation (2), we get 2 (- 1 – 2y) – 3y = 12 – 2 – 4y – 3y = 12 – 2 – 7y = 12 7y = – 2 – 12 ∴ y = \(\frac{-14}{7}\)= -2 Substituting y = – 2 in equation (1), we get x + 2 (- 2) = – 1 x = – 1 + 4 x = 3 ∴ The solution is (3, – 2)

Solve equations by using the substitution method.x + 2y = – 1 2x – 3y = 12

Answer»

Given:

x + 2y = -1 ……. (1)

2x – 3y = 12 …….. (2)

From equation (1)

x + 2y = -1

⇒ x = – 1 – 2y

Substituting x = – 1 – 2y in equation (2), we get

2 (- 1 – 2y) – 3y = 12

– 2 – 4y – 3y = 12

– 2 – 7y = 12

7y = – 2 – 12

∴ y = \(\frac{-14}{7}\)= -2

Substituting y = – 2 in equation (1), we get

x + 2 (- 2) = – 1

x = – 1 + 4

x = 3

∴ The solution is (3, – 2)