Question

$<b><i>hey friends!$

⏩ if x = 3 is the solution of the equation 2x² + px = 15, calculate the value of p and hence find the other solution. ⏪

please help... answer behind is p = -1 ( which I have got ) and x = -2½ ( which I'm not able to get )
thanks and don't spam ❌❌❌

Answer 1

Answer -

As its given, x = 3 therefore substitute X = 3 in

2x² + px = 15

2 ( 3)² + p ( 3) = 15

2 × 9 + 3p = 15

18 + 3p = 15

18 - 15 = -3p

hence

3 = -3p => p = -3/3 => -1

Answer 2

Heya mate,

Here is your answer,. ⬇️⬇️

${ANSWER :-}$

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$<i>$ Here, putting, x = 3, in the 2x^2 + px = 15, we have,

2(3)^2 + p(3) = 15

=> 2 * 9 + 3p = 15

=> 3p = 15 - 18 = - 3

=> p = - 3 / 3 = - 1

Thus, p = - 1 . ⬅️
_ _ _ _ _ _ _ _ _ _ _ _

Now, we have, putting p = - 1 in the equation, 2x^2 + px = 15,

2x^2 + (-1)x = 15

=> 2x^2 - x = 15

=> 2x^2 - x - 15 = 0

=> 2x^2 - 6x + 5x - 15 = 0

=> 2x(x - 3) + 5(x-3) = 0

=> (x - 3)( 2x + 5) = 0 ⬆️

Now, (x - 3) = 0
=> x - 3 = 0
=> x = 3 ⬅️ [ given]

Again, (2x + 5) = 0
=> 2x + 5 = 0
=> 2x = - 5
=> x = - 5/2 ⬅️ [ required]

➡️ Hence, the value of p is (-1) and the other solution for x is ( - 5/2).

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$<b>$ Hope this helps,.

If helps, please mark 'thanks'

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REGARDS, ARNAB ✌️

THANK YOU