SOLUTION: Method of Substitution 5. Find the point of intersection of each pair of lines. a) 2x=y+5 3x+y=-9 Pleaseeeeeeee and thank you very much!!!!!

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Question 181847: Method of Substitution
5. Find the point of intersection of each pair of lines.
a) 2x=y+5
3x+y=-9
Pleaseeeeeeee and thank you very much!!!!!
Found 2 solutions by solver91311, josmiceli:
Answer by solver91311(24713) About Me  (Show Source):
You can put this solution on YOUR website!


Solve this the same way I showed you in question 181852


http://www.algebra.com/algebra/homework/quadratic/Quadratic_Equations.faq.question.181852.html


John

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
the intersection is the point (x,y) that
solves both equations
(a) 2x+=+y+%2B+5
(b) 3x+%2B+y+=+-9
Subtract y from both sides of (a)
(b) 3x+%2B+y+=+-9
(a) 2x+-+y++=+5
Add (a) and (b)
5x+=+-4
x+=+-%284%2F5%29
Now plug this value of x back into
either (a) or (b)
(a) 2%2A%28-%284%2F5%29%29+-+y++=+5
-%288%2F5%29+-+y+=+5
y+=+-%288%2F5%29+-+5
y+=+-%288%2F5%29+-+25%2F5
y+=+-%2833%2F5%29
The intersection is at x+=+-%284%2F5%29 and y+=+-%2833%2F5%29
check answer:
(b) 3x+%2B+y+=+-9
(b) 3%2A%28-%284%2F5%29%29+%2B+%28-%2833%2F5%29%29+=+-9
-%2812%2F5%29+-+%2833%2F5%29+=+-9
-%2845%2F5%29+=+-9
-9+=+-9
OK
(a) 2x+-+y++=+5
2%2A%28-%284%2F5%29%29+-+%28-%2833%2F5%29%29+=+5
-%288%2F5%29+%2B+33%2F5+=+5
25%2F5+=+5
5+=+5
OK