Please solve Equation Qs

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sachin85's picture
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Q1. How many common solution exists between (a – b)x2 +(b – c)x +(c – a) = 0 and (c – a)x2 +(b – c)x +(a – b) = 0 ?
a. 0
b. 1
c. 2
d. None of these

Q2. How many triples (x, y, z) of positive integers satisfy the following equation
 3x + 4y = 5z.
a. 0
b. 1
c. 2
d. None of these

 

manjurul (not verified)
manjurul's picture
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Q2. There exist only one

Q2. There exist only one triplet

(2, 2, 2)

answer is b

It can be proved but i guess the logic involved is beyond CAT standard

jigar_er_civil's picture
User offline. Last seen 2 years 52 weeks ago. Offline
Joined: 2007-09-03
Points: 830
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ans

Q1. How many common solution exists between (a – b)x2 +(b – c)x +(c – a) = 0 and (c – a)x2 +(b – c)x +(a – b) = 0 ?
a. 0
b. 1
c. 2
d. None of these

Here equation (a – b)x2 +(b – c)x +(c – a) = 0 --------(1)
and (c – a)x2 +(b – c)x +(a – b) = 0 ?---------(2)

so equating both

ax^2-bx^2+bx-cx+c-a=cx^2-ax^2+bx-cx+a-b

so 2a(x^2-1)-b(x^2-1)-c(x^2-1)=0

so X^2-1=0

so x=+/- 1

ans=c

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