SOLUTION: Let c be a constant. The simultaneous equations x-y=2 , cx+y=3 have a solution (x, y ) inside Quadrant I if and only if (A) c = -1 (B) c > -1 (C) c < 3/2 (D) 0 < c < 3/2 (E) - l

Algebra ->  Equations -> SOLUTION: Let c be a constant. The simultaneous equations x-y=2 , cx+y=3 have a solution (x, y ) inside Quadrant I if and only if (A) c = -1 (B) c > -1 (C) c < 3/2 (D) 0 < c < 3/2 (E) - l      Log On


   

Question 1064998: Let c be a constant. The simultaneous equations
x-y=2 , cx+y=3
have a solution (x, y ) inside Quadrant I if and only if
(A) c = -1 (B) c > -1 (C) c < 3/2 (D) 0 < c < 3/2 (E) - l < c < 3/2
Answer by josgarithmetic(39616) About Me  (Show Source):
You can put this solution on YOUR website!
Choice E
-1%3Cc%3C3%2F2

If using Elimination Method to find x and y,
system%28x=5%2F%28c%2B1%29%2Cy=%283-2c%29%2F%28c%2B1%29%29

x and y both must be positive for quadrant 1.

x=5%2F%28c%2B1%29%3E0
c%2B1%3E0
c%3E-1


y=%283-2c%29%2F%28c%2B1%29%3E0

If choosing numerator and denominator both positive,
system%283-2c%3E0%2CAND%2Cc%2B1%3E-1%29

c%3C3%2F2 and c%3E-1

-1%3Cc%3C3%2F2

Trying both numerator and denominator as negative will not work.