Question

2. 15-3x = (2x + 1)(2x - 1)-(2x - 1)(2x+3).
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Answer 1

Answer :

The required solution is x = - 13

Solution :

15 - 3x = (2x + 1) (2x - 1) - (2x - 1) (2x + 3)

⇒ 15 - 3x = (2x - 1) {(2x + 1) - (2x + 3)}

⇒ 15 - 3x = (2x - 1) (2x + 1 - 2x - 3)

⇒ 15 - 3x = (2x - 1) (- 2)

⇒ 15 - 3x = - 4x + 2

⇒ - 3x + 4x = 2 - 15

⇒ x = - 13

Verification :

• Putting x = - 13 in Left Hand Side of the given equation, we get

15 - 3x = 15 - 3 (- 13) = 15 + 39 = 54

• Putting x = - 13 in Right Hand Side f the given equation, we get

(2x - 1) (2x + 1) - (2x - 1) (2x + 3)

= {2 (- 13) - 1} {2 (- 13) + 1}

- {2 (- 13) - 1} {2 (- 13) + 3}

= (- 26 - 1) (- 26 + 1) - (- 26 - 1) (- 26 + 3)

= (- 27) (- 25) - (- 27) (- 23)

= (27 * 25) - (27 * 23)

= 27 (25 - 23)

= 27 * 2 = 54

Thus, x = - 13 is verified as the required solution.

Answer 2

Answer: X = -13

Step-by-step explanation:

Different method :-

15 - 3x = (2x + 1 )(2x - 1) - ( 2x -1 )( 2x + 3)

Step 1 :- use formula to simplify (2x + 1)(2x - 1)( a + b ) ( a - b ) = a^2 - b^2

》Do binomial multiplication to simplify (2x - 1 ) ( 2x + 3 )

15 - 3x = (2x)^2 - (1)^2 - [4x^2 + 6x - 2x -3x]

Step 2 :- further simplify

15 -3x = 4x^2 - 1 - [4x^2 + 6x - 2x -3 ]

15 -3x = 4x^2 - 1 - 4x^2 - 6x + 2x +3

》 4x^2 and - 4x^2 get cancel

15 -3x = - 1 - 6x + 2x +3

15 - 3x = 2 - 4x

15 -3x -2 + 4x = 0

13 + X = 0

X = -13

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☆ verification is already provided in the above answer :)

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