Q). If α, β are the roots of 5×2 + 5x + 6 = 0, then (1 + α) (1 + β) =
A) 4/5
B) 3/5
C) 6/5
D) -6/5
View Answer
C) 6/5
Explanation: a = 5, b = 5, c = 6
α+β = -b/a = -5/5 = -1
αβ = c/a = 6/5
(1+ α)(1+ β) = 1 +( α+β)+ αβ
= 1+(-1)+6/5
= 6/5
Q). If the difference of two numbers is 5 and their product is 84, then the numbers are
A) 14,6
B) 12,7
C) 21,4
D) 14,9
View Answer
B) 12,7
Explanation: Let the two numbers are α and β
α – β = 5, αβ = 84
(α + β)2 = (α – β)2 + 4 x β
= (5)2 + 4 x 84
= 25 + 336
= 361
α + β = √361 = 19
α + β = 19
α – β =5
_______
2 α = 24
_______
⇒ α = 12, β = 19 – α
=19-12 = 7
∴ That numbers are 12 and 7
Q). If the perimeter of a rectangular room is 34 and the length of the diagonal is 13, then the dimensions of the room are
A) 7,6
B) 11,6
C) 12,5
D) 12,6
View Answer
C) 12,5
Explanation: perimeter of a rectangle = 34
2(l + b) = 34 ⇒ l + b = 17
length of the diagonal = = 13
l2 + b2 = 169
(l + b)2 = l2 + b2 + 2/b
(17)2 = 169 + 2lb
⇒ 289- 169 = 2lb
2lb = 120 ⇒ lb = 60
(l – b)2= (l + b)2-4lb
= (17)2-4x 60 = 289-240 = 49
L – b=-749 = 7
l + b= 17
l – b =27
________
2l = 24 ⇒ l = 12, b = 17 – 12 = 5
∴ The dimensions of the room are 12 and 5
Q). If 9x + 11y = 51 and 11x + 9y = 49, then x =
A) -1
B) -2
C) 1
D) 2
View Answer
D) 2
Explanation: 9x +11y = 51 and 11x + 9y = 49
by adding given equations are 20x + 20y = 100
⇒x + y = 5
y = 5-x
11x + 9 (5-x) = 49
11x + 45-9x = 49
2x = 4 ⇒x = 2
Q). If the pair of equations a1x + b1y + c1= 0 and a2x + b2y + c2 = 0 has unique solution, then
A) a1/ a2 = b1/ b2
B) a1/ a2 ≠ b1/ b2
C) b1/ b2≠ c1/ c2
D) b1/ b2= c1/ c2
View Answer
B) a1/ a2 ≠ b1/ b2
Q). 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 = -x2 ⇒ y = mx2 (m < 0)
passes through Q3 and Q4
Q). The line x = 2017 is
A) Slope not defined
B) Parallel to y-axis
C) Slope not defined and Parallel to y-axis
D) None
View Answer
C) Slope not defined and Parallel to y-axis
Explanation: The line x = k parallel to Y – axis so, it has no slope