The Equation →
What is the value of a?
A) -16
B) -3
C) 3
D) 16
Answers
EXPLANATION.
Equation :
⇒ 24x² + 25x - 47/ax - 2 = -8x - 3 - 53/ax - 2.
⇒ 24x² + 25x - 47/ax - 2 = (-8x - 3)(ax - 2) - 53/ax - 2.
Both (ax - 2) will get cancel,
⇒ 24x² + 25x - 47 = (-8x - 3)(ax - 2) - 53.
⇒ 24x² + 25x - 47 = (-8ax² + 16x - 3ax + 6) - 53.
⇒ 24x² + 25x - 47 = -8ax² + 16x - 3ax + 6 - 53.
⇒ 24x² + 25x - 47 = -8ax² - 3ax + 16x - 47.
⇒ 24x² + 8ax² + 3ax + 25x - 16x = 0.
⇒ (24 + 8a)x² + 3ax + 9x = 0.
⇒ (24 + 8a)x² + 3x( a + 3) = 0.
⇒ ( 3 + a)8x² + 3x( a + 3) = 0.
⇒ ( a + 3)( 8x² + 3x) = 0.
⇒ a ≠ 2/a.
⇒ a = -3.
Value of a = -3.
Option [ B] is correct answer.
MORE INFORMATION.
Nature of roots,
The term b² - 4ac is called discriminant of the equation. it is denoted by Δ or D.
(A) = Suppose a, b, c ∈ R and a ≠ 0 then,
(1) = if D > 0 ⇒ Roots are real and unequal.
(2) = if D = 0 ⇒ Roots are real and equal and each equal to -b/2a.
(3) = if D < 0 ⇒ Roots are imaginary and unequal or complex conjugate.
(B) = Suppose a, b, c ∈ Q , a ≠ 0 then,
(1) = if D > 0 and D is perfect square ⇒ Roots are unequal and rational.
(2) = if D > 0 and D is not perfect square ⇒ Roots are irrational and unequal.
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Equation
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
- ⇒ 24x² + 25x - 47/ax - 2 = -8x - 3 - 53/ax - 2.
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
- ⇒ 24x² + 25x - 47/ax - 2 = (-8x - 3)(ax - 2) - 53/ax - 2.
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
- ⇒ 24x² + 25x - 47 = (-8x - 3)(ax - 2) - 53.
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
- ⇒ 24x² + 25x - 47 = (-8ax² + 16x - 3ax + 6) - 53.
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
- ⇒ 24x² + 25x - 47 = -8ax² + 16x - 3ax + 6 - 53.
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
- ⇒ 24x² + 25x - 47 = -8ax² - 3ax + 16x - 47.
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
- ⇒ 24x² + 8ax² + 3ax + 25x - 16x = 0.
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
- ⇒ (24 + 8a)x² + 3ax + 9x = 0.
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
- ⇒ (24 + 8a)x² + 3x( a + 3) = 0.
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
- ⇒ ( 3 + a)8x² + 3x( a + 3) = 0.
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
- ⇒ ( a + 3)( 8x² + 3x) = 0
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
- ⇒ a ≠ 2/a.
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
- ⇒ a = -3.
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
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