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JAMB Mathematics Past Questions & Answers - Page 148

736.

If 3x14)12>14x, then the interval of values of x is

A.

x > 13

B.

x < 13

C.

x < 14

D.

x < 916

E.

x > 916

Correct answer is E

3x(14)12>14x

= 3x412>14x

= 3x2>14x

= 3x+x>14+24x>94

x>916

737.

The minimum point on the curve y = x2 - 6x + 5 is at

A.

(1, 5)

B.

(2, 3)

C.

(-3, -4)

D.

(3, -4)

Correct answer is D

Given the curve y=x26x+5

At minimum or maximum point, dydx=0

dydx=2x6

2x6=0x=3

Since 3 > 0, it is a minimum point.

When x = 3, y=326(3)+5=4

Hence, the turning point has coordinates (3, -4).

738.

A force of 5 units acts on a particle in the direction to the east and another force of 4 units acts on the particle in the direction north-east. The resultants of the two forces is

A.

3 units

B.

3 units

C.

41+202 units

D.

41202 units

Correct answer is C

Force to the east = 5 units

force to the North - east = 4 units.

Resultant of the two forces is the square root

52 + 42 = 41 and plus the sum of its resistance

5 x 42 = 202

= 41+202 units

739.

Simplify aba+b - a+bab

A.

4abab

B.

4aba2b2

C.

4aba2b

D.

4aba2b2

Correct answer is B

aba+b - a+bab = (ab)2(a+b) - (a+b)2(ab0

applying the principle of difference of two sqrt. Numerator = (a - b) + (a + b) (a - b) - (a + b)

= (a = b + a = b)(a = b - a = b)

2a(-2b) = -4ab

= 4ab(a+b)(ab)

= 4aba2b2

740.

If the four interior angles of a quadrilateral are (p + 10)°, (p - 30)°, (2p - 45)°, and (p + 15)°, then p is

A.

125o

B.

82o

C.

135o

D.

105o

E.

60o

Correct answer is B

Sum of interior angles of a polygon = (2n - 4) x 90

where n is the no. of sides

sum of interior angles of the quad. = ({2 x 4} -4) x 90

(8 - 4) x 90 = 4 x 90o

= 360o

(p + 10)o + (p - 30)o + (2p - 45)o + (p + 15)o = 360o

p + 10o + p - 30o + 2p - 45o + p + 15 = 360o

5p = 360o + 50o

= 82o