Quadratic Equation
Direction: In each of these questions, two equations are given. You have to solve these equations and find out the values of x and y and Give answer
( 1 ) if x < y
( 2 ) if x > y
( 3 ) if x ≤ y
( 4 ) if x ≥ y
( 5 ) if x = y
- Ⅰ. 16x2 + 20x + 6 = 0
Ⅱ.10y2 + 38y + 24 = 0
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As per the given above equations , we can say that
Ⅰ.
16x2 + 20x + 6 = 0
⇒ 16x2 + 12x + 8x + 6 = 0
Ⅱ.
10y2 + 38y + 24 = 0
⇒ 10y2 + 30y + 8y + 24 = 0
⇒ 10y(y + 3) + 8(y + 3) = 0Correct Option: B
As per the given above equations , we can say that
Ⅰ. 16x2 + 20x + 6 = 0
⇒ 16x2 + 12x + 8x + 6 = 0
⇒ 4x(4x + 3) + 2(4x + 3) = 0
⇒ (4x + 2)(4x + 3) = 0
Ⅱ.10y2 + 38y + 24 = 0⇒ x = - 3 , - 2 4 4
⇒ 10y2 + 30y + 8y + 24 = 0
⇒ 10y(y + 3) + 8(y + 3) = 0
⇒ (10y + 8)(y + 3) = 0
∴ x > y⇒ y = - 3, - 4 5
From above both equations it is clear that correct answer is x > y .
- Ⅰ. 17x2 + 48x = 9
Ⅱ.13y2 = 32y –12
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From the given above equations , we have
From equation Ⅰ.
17x2 + 48x − 9 = 0
⇒ 17x2 + 51x − 3x − 9 = 0
From equation Ⅱ.
13y2 − 32y + 12 = 0
⇒ 13y2 − 26y − 6y + 12 = 0Correct Option: A
From the given above equations , we have
From equation Ⅰ.
17x2 + 48x − 9 = 0
⇒ 17x2 + 51x − 3x − 9 = 0
⇒ 17x(x + 3) − 3(x + 3) = 0
⇒ (17x − 3)(x + 3) = 0⇒ x = - 3, 3 17
From equation Ⅱ.
13y2 − 32y + 12 = 0
⇒ 13y2 − 26y − 6y + 12 = 0
⇒ 13y(y − 2) − 6(y − 2) = 0
⇒ (13y − 6)(y − 2) = 0⇒ y = 2, 6 13
- The roots of the equation a2x2 - 3abx + 2b2 = 0 are
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The given quadratic equation is
a2x2 - 3abx + 2b2 = 0 &⇒ a 2 x 2 - 3abx + 2b 2 = 0
⇒ ax ( ax - 2b ) - b ( ax - 2b ) = 0
⇒ ( ax - 2b ) ( ax - b ) = 0
⇒ ax - 2b = 0 or ax - b = 0⇒ x = 2b or x = b a a Correct Option: B
The given quadratic equation is
a 2 x 2 - 3abx + 2b 2 = 0 &⇒ a 2 x 2 - 3abx + 2b 2 = 0
⇒ ax ( ax - 2b ) - b ( ax - 2b ) = 0
⇒ ( ax - 2b ) ( ax - b ) = 0
⇒ ax - 2b = 0 or ax - b = 0⇒ x = 2b or x = b a a
Thus, the two roots of the given quadratic equation are2b and b a a
- If α and β are the roots of the quadratic equation ax 2 + bx + c = 0, the value of α3 + β3 is
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According to question , we can say that
Since α and β are the roots of the quadratic equation
ax 2 + bx + c = 0∴ α + β = − b and αβ = c a a Correct Option: B
According to question , we can say that
Since α, β are the roots of the quadratic equation
ax 2 + bx + c = 0∴ α + β = − b and αβ = c a a
Now, α 3 + β 3 = ( α + β ) 3 - 3αβ( α + β )= - b 3 - 3 x c x - b a a a α3 + β3 = - b 3 + 3bc = - b2 + 3abc a3 a2 a3 Hence , α3 + β3 = b ( 3ac - b2 ) a 3
- For what value of k the quadratic polynomial 3z2 + 5z + k can be factored into product of real linear factors ?
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We have , the given quadratic eq. 3z 2 + 5z + k
Comparing it with ax 2 + bx + c = 0, we get a = 3, b = 5, c = k
Now , D = b2 - 4ac = 25 - 12k
For equal linear factors to exist, D ≥ 0
⇒ 25 - 12k ≥ 0
⇒ 25 ≥ 12kCorrect Option: B
We have , the given quadratic eq. 3z 2 + 5z + k
Comparing it with ax 2 + bx + c = 0, we get a = 3, b = 5, c = k
Now , D = b2 - 4ac = 25 - 12k
For equal linear factors to exist, D ≥ 0
⇒ 25 - 12k ≥ 0
⇒ 25 ≥ 12k⇒ k ≤ 25 12
quadratic polynomial can be factored into the product of real linear factors.Therefore, the set of real numbers ≤ 25 gives the set of value of k for which the given 12