PLEASE help!!! medal awarded!! How can x + 8 = -x + 7 be set up as a system of equations?

a.)
y = x + 8
y = -x + 7

b.)
y = x + 8
y = -3x + 7

c.)
y = x + 5
y = -2x + 11

d.)
y = 8
y = -3x + 7

Question

PLEASE help!!! medal awarded!!                                         How can x + 8 = -x + 7 be set up as a system of equations?

 
a.)
y = x + 8
y = -x + 7

 
b.)
y = x + 8
y = -3x + 7

 
c.)
 y = x + 5
 y = -2x + 11

 
d.)
 y = 8
 y = -3x + 7

the_fizicx99 · Answer

A ;p

anonymous · Answer

how do you know

the_fizicx99 · Answer

Because, if y = x + 8 and y = -x + 7

Then plug in x + 8 for y into y = -x + 7

x+8 = -x + 7

anonymous · Answer

If you were to use the substitution method to solve the following system, choose the new equation after the expression equivalent to y from the first equation is substituted into the second equation. 

15x - y = -6 
5x - 3y = -13

the_fizicx99 · Answer

Make one question per post, it lags up :c