Question

Solve the following simultaneous equations by using the substitution method :
x+ y =15, y = x + 3​

Answer 1

Answer:

X + y = 15

Y = X + 3

X + X + 3 = 15

2X + 3 = 15

2X = 15 - 3

2X = 12

X = 12/2 = 6

Answer 2

Answer:

x+x+3 = 15 ( because y = x+3 )

2x+3 = 15

2x = 15-3

2x = 12

x = 12/2

x = 6