SOLUTION: Hi, could you help to find the coordinates of the point where the lines with the following equations intersect 8x + 5y = -7 -3x + y = -1/4

Algebra ->  Graphs -> SOLUTION: Hi, could you help to find the coordinates of the point where the lines with the following equations intersect 8x + 5y = -7 -3x + y = -1/4       Log On


   

Question 1157649: Hi, could you help to find the coordinates of the point where the lines with the following equations intersect
8x + 5y = -7
-3x + y = -1/4

Found 2 solutions by solver91311, josmiceli:
Answer by solver91311(24713) About Me  (Show Source):
You can put this solution on YOUR website!


Multiply the second equation by -5:




Add the equations, term by term





Substitute this value into either equation and solve for







Therefore, the unique ordered pair that satisfies each of the equations is


John

My calculator said it, I believe it, that settles it

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
(1) +8x+%2B+5y+=+-7+
(2) +-3x+%2B+y+=+-1%2F4+
Multiply both sides of (2) by +8+
Multiply both sides of (1) by +3+
Then add the equations
(1) +24x+%2B+15y+=+-21+
(2) +-24x+%2B+8y+=+-2+
---------------------------
+23y+=+-23+
+y+=+-1+
Plug this result back into (1) or (2)
(1) +8x+%2B+5y+=+-7+
(1) +8x+%2B+5%2A%28-1%29+=+-7+
(1) +8x+-+5+=+-7+
(1) +8x+=+-2+
(1) +x+=+-1%2F4+
( -1/4 , -1 ) answer
------------------------------
check:
(2) +-3x+%2B+y+=+-1%2F4+
(2) +-3%2A%28+-1%2F4+%29+%2B+%28-1%29+=+-1%2F4+
(2) +3%2F4+-+1+=+-1%2F4+
(2) +-1%2F4+=+-1%2F4+
OK
You can check equation (1)