Question:
If x y+ 5 = 4 and y x+ 5 = -4, then what is (x + y) equal to?
If x y+ 5 = 4 and y x+ 5 = -4, then what is (x + y) equal to?
Options:
- a) 0
- b) 1
- c) 4
- d) 5
- a) 0
- b) 1
- c) 4
- d) 5
correct answer : a)
Explanation:
xy + 5 = 4y
xy + 5 =-4x
– – +
0 = 4(x + y)
Þ x + y = 0
xy + 5 = 4y
xy + 5 =-4x
– – +
0 = 4(x + y)
Þ x + y = 0