Saturday

August 23, 2014

August 23, 2014

Posted by **ayan** on Tuesday, April 16, 2013 at 3:41am.

- math -
**Reiny**, Tuesday, April 16, 2013 at 8:59ammmmh, been messing around this for a while

from 1st:

x(x + y + 1) = 81

from 2nd:

y(y + x + 1) = 51

divide them:

x/y = 81/51

81y = 51x -----> y = 51x/81

sub that into x^2 + xy + x = 81

81x^2 + x(51x/81) + x = 81

81x^2 + 51x^2 + 81x = 6561

132x^2 + 81x - 6561 = 0

x = (-81 ± √3470769)/ 264

= (-81 ± 1863)/264 , which reduces to

= 27/4 or -81/11

ahhh, I guess we could have factored it, lol

132x^2 + 81x - 6561 = 0

44x^2 + 27x - 2187 = 0

(4x - 27)(11x + 81) = 0

anyway, too late,

if x = 27/4 , from y = 51x/81 --> y = 17/4

if x = -81/11, ------> y = -51/11

for first point:

x + y = 27/4 + 17/4 = 44

for 2nd point:

x+y = negative

so for your condition:

x+y = 44

**Related Questions**

math - The point (x,y) lies on both conics x2+xy+x=81 and y2+xy+y=51. Given that...

math - The point (x,y) lies on both conics x2+xy+x=81 and y2+xy+y=51. Given that...

Math - A curve has equation y= 2 + x - x^2. Find coordinates of 3 unknown points...

Math - The point (-8,3) lies on the terminal arm of angle theta in standard ...

trig - If point G(a,b) lies on the terminal side of angle theta in standard ...

advanced functions - Angle a lies in the second quadrant and sina=7/25. a) ...

Math - Point (k,3) lies on the line whose equation is x-2y=-2. What is the value...

Physics(Please check) - There is a PV diagram with ABC and the cycle is moving ...

maths - Angle a lies in the second quadran and angle b lies in the third ...

Math Help! - A.) Determine "a" and "k" so both points are on the graph of the ...