ENGRTOMBA2018
fla162
Which of the following equations represents a line on xy-plane that includes exactly only one point P(Xp; Yp) with integer coordinates (Xp and Yp are both integer numbers)?
a) y= 2x
b) 2x-2y+1=0
c) y-5=3x
d) 2y-√2.x =0
e) 2y= x+2
Easiest way is to do POE for the options to arrive at the correct answer. Incorrect options will either provide 0 integer coordinate pairs or will provide >1 integer coordinate pairs.
a) y= 2x ,
(0,0) m (1,2) etc. Eliminateb) 2x-2y+1=0 -->
y=x+0.5 , no integer coordinate pairs. Eliminatec) y-5=3x --->
y=3x+5, (0,5), (1,8) etc. Eliminated) 2y-√2.x =0 --->
Only case possible = (0,0). Rest of them will be functions of \(\sqrt{2}\). Keepe) 2y= x+2 --->
y=x/2+1 ---> (2,2) , (4,3) etc. EliminateThus, D is the correct answer.
Hope this helps.
In option d, if I write it as :
y=(√2*x)/2
>> y=x/√2
Then taking 'x' as 8 (which can be written as √2*2), I get the value of 'y' as 2
This case also satisfies the criteria and not just (0,0).
Do u agree or am I missing something?