Question

Which is the best first step and explanation for solving this system of equations? 3x+y=7 x+y=3

Answer 1

(3x+y) - (x+y) = 7 - 3

subtract equal quantities from both sides of the first equation.

Answer 2

x = 2 and y = 1

Explanation:

Given equations are :

3x+y=7 ....(1)

x+y=3 ....(2)

Subtract equation (1) and (2) we get :

3x+y-(x+y) = 7-3

3x+y-x-y = 4

3x-x = 4

2x = 4

x = 2

Now put the value of x in equation (2)

2+y=3

y=3-2

y = 1

Hence, the solution of the equations are x = 2 and y = 1.