Question

[6.03] Solve the following system.
x − y = 10
x + y = 4

(−3, 7)

(−7, 3)

(7, 3)

(7, −3)

Answer 1

add bouth equations and see what you get

Answer 2

x − y = 10 -(1)
x + y = 4 -(2)

(1) + (2):
(x − y) + (x + y) = 10 + 4

What do you get from here?

Answer 3

Another option is to solve either equation for either y or x, then plug the result back into the equation using substitution.

Answer 4

you get 14 ?

Answer 5

x − y = 10
x + y = 4
______________ +
2x = 14

Answer 6

you can find value of x from here. Later use it to find value of y

Answer 7

7

Answer 8

right x=7, now plug this in any original equation and solve it for y

Answer 9

Its 3 ?

Answer 10

be carefull with signs

Answer 11

7,3 or 7,-3

Answer 12

if foe example you use this equation to find y:
x + y = 4
you get: 7+y=4
so y=4-7=-3
and the answer will be: (7,-3)