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

(−3, 7)

(−7, 3)

(7, 3)

(7, −3)

Question

[6.03] Solve the following system.
x − y = 10
x + y = 4 

 (−3, 7) 

 (−7, 3) 

 (7, 3) 

 (7, −3)

anonymous · Answer

add bouth equations and see what you get

callisto · Answer

x − y = 10  -(1)
x + y = 4    -(2)

(1) + (2): 
(x − y) + (x + y) = 10 + 4 

What do you get from here?

anonymous · Answer

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

anonymous · Answer

you get 14 ?

anonymous · Answer

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

anonymous · Answer

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

anonymous · Answer

7

anonymous · Answer

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

anonymous · Answer

Its 3 ?

anonymous · Answer

be carefull with signs

anonymous · Answer

7,3 or 7,-3

anonymous · Answer

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)