Aptitude Algebraic Expressions Test Paper 2

Answer: B

Explanation:

Given equation is
(2x+3) (3x+1) = (3x-1) (2x-1)
= 6x² + 11x + 3
= 6x² - 5x + 1
= 16x +2
16x = -2
x = -

Answer: D

Explanation:

Roots are equal if discriminant
b² - 4ac = 0
In given equation:
(P+1)² - 4.41 = 0
(p+1)² = 16 = (4)²
p+1 = +4, -4
p= 3 or - 5

Answer: A

Explanation:

Let the speed of the car is x km/hr. Then
Speed = distance/ time:

=2

=>

x² - 5x - 750 = 0
x² - 30x + 25x - 750 = 0
(x - 30) (x + 25) = 0
x =30 or x = -25
The negative value of x is inadmissible; therefore the speed of the car is 30 km/hr.

Answer: A

Explanation:

The given equation:

x² - 3x - 4x -12 = - 6x +18
x² - x - 30 = 0
x² + 5x - 6x - 30 = 0
(x+5) (X-6) = 0
x = - 5 or 6

Answer: C

Explanation:

If α and β be the roots of the equation:
Then α + β = , and αβ =

Also, α = 2β. Then
3β==>β =

And,
2β²=

∴

=>=

=>2b²=9ac