11) If = 5 and =6 , then x, y is …………………
A) (9, 14)
B) (14,9)
C) (7, 9)
D) (14,18)
View Answer
B) (14,9)
Explanation:
= 5
⇒
= 5
⇒ 3x+7y = 105
=6
=6
9x – 2y = 108 …………….(1)
3(3x + 7y = 105) = 9x + 21y = 315 …………….(2)
by solving (1) and (2)
9x — 2y= 108
9x + 21y = 315
(-) (-) (-)
____________
-23y = -207
Y = 9
Now substitute y = 9 in 3x + 7y = 105
3x + 7 x 9 = 105
⇒ 3x + 63 = 105
⇒ 3x = 105 – 63 = 42
⇒ x = 14
∴ x = 14 and y = 9
12) The graph of y + x2 = 0 lies in the quadrants
A) Q1 ,Q2
B) Q2 ,Q3
C) Q3 ,Q4
D) Q4 ,Q1
View Answer
C) Q3 ,Q4
Explanation:y = m x2 , m < 0, the graph lies in Q3 and Q4
∴ y = – x2 lies in Q3 and Q4
13) Solution of the equations √2x + √3y = 0 and √3x – √8y = 0 is ………………………
A) x = 1, y = 0
B) x = 0;y=l
C) x=1,y=1
D) x = 0, y = .0
View Answer
D) x = 0, y = .0
14) If 2X + 3y = 17 and 2X + 2 – 3y + 1 = 5, then y = …………………….
View Answer
A) 2
Explanation:Let 2X = a and 3y = b
2X + 3y = 17 ⇒ a + b = 17 ⇒ b = 17 – a
2X + 2 – 3y x 31 = 5
⇒ 2X . 2 2 – 3y . 31 = 5
⇒ 4a -3b = 5
=> 4a-3(17-a) = 5=>4a-51+3a = 5
=> 7a = 56 => a = 56/7 = 8
∴a = 8 => 2x = 8 => 2x = 23 => x = 3
=> 4(8) -3b = 5 => 32 -3b = 5
=> 27 = 3b => b = 9
∴ b = 9=>3y = 9=>3y = 32=>y = 2
15) x + y = 2015 has ….. number of solutions.
A) 10
B) 2014
C) 20
D) infinite
16) The condition for a x2 + bx + c = 0 to be a quadratic equation is
A) a, b, c ∈R
B) a=0,c ≠0
C) a ≠0
D) a=0,b ≠0
17) The difference between two consecutive positive integers is
18) If α,β are the roots of ax2 + bx + c = 0, then 1/α + 1/β =
A) –b/c
B) b/c
C) c/b
D) –c/b
View Answer
A) –b/c
Explanation:1/α + 1/β =
=
= -b/c
19) If 65 diagonals are drawn to a polygon of ‘n’ sides, then what is the value of ‘n’?
A) 10
B) 20
C) 13
D) None
View Answer
C) 13
Explanation:No. of sides of polygon = n
No. of diagonal of a polygon having ‘n’ sides =
= 65 ⇒ n
2 – 3n = 130
⇒ n
2 -3n-130 = 0 ⇒ n
2 + 10n-13n-130=0
⇒ n (n + 10) – 13 (n + 10) =0
⇒ (n + 10) (n – 13) = 0 ⇒ n = 13
∴ No. of sides are n = 13
20) Find the 10th term in A.P. 5, 1, -3, -7,…………….
View Answer
A) -31
Explanation:a = 5, d=1-5 = 4
10th term = a10 = a + 9d,= 5 + 9(-4)
= 5 -36
= -31
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