Question

Solve, using the substitution method. 2x + 3y = 3 x + 2y = 1 (1, 4) (0, –2) (3, –1) (7, -5/2)

Answer 1

x = 3 and y = -1

Explanation:

using substitution method

let;

2x + 3y = 3 ................ equation 1

x + 2y = 1 ...................... equation 2

from equation 2

x + 2y = 1 ...................... equation 2

x = 1 - 2y .................... equation 3

substitute for x = 1 - 2y in equation 1

2x + 3y = 3 ................ equation 1

2 ( 1 - 2y) + 3y = 3

Open the bracket

2 -4y + 3y = 3

2 - y = 3

-y = 3 - 2

-y = 1

multiply both sides by -

therefore y = -1

put y = -1 in equation 3

x = 1 - 2y .................... equation 3

x = 1 - 2 ( -1)

x = 1 + 2

x = 3

therefore x = 3 and y = -1

to check for the correctness of your answer put the value of x = 3 and y = -1 in any of the equations. e.g

x = 1 - 2y .................... equation 3

3 = 1 - 2(-1)

3= 3................................. proved