Question

Solve the system using elimination.
3x + 10y = -4
2x + 2y = 2
([?], [ ])

Answer 1

x = 2

y = -1

Explanation:

3x + 10y = -4

- 10x + 10y = 10

7x + 0 = -14

7x = 14

x = 2

2x + 2y = 2

2×2 + 2y = 2

4 + 2y = 2

2y = -2

y = -1

Answer 2

Explanation:

that normally means we want to add our subtract a certain of the 2 equations, so that we are led with one summary equation with only one variable.

the easiest way here is possibly to multiply the second equation by 5 (to get also 10y) and then subtract it from the first equation :

3x + 10y = -4

- 10x + 10y = 10

-----------------------

-7x + 0 = -14

7x = 14

x = 2

2x + 2y = 2

gives us then

2×2 + 2y = 2

4 + 2y = 2

2y = -2

y = -1

x = 2

y = -1