Given that (3x – 8)*(3x + 2) – (4x – 11)*(2x + 1) = (x – 3)(x + 7). What is the value of 9x?

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09 Jan 2020 Solve

Given that (3x – 8)*(3x + 2) – (4x – 11)*(2x + 1) = (x – 3)(x + 7). What is the value of 9x?

OPtion

1) 1
2) 2
3) 3
4) 6
5) 4
6) 128
7) 36
8) 8
9) 16
10) None of these

Solution

(3x - 8) (3x + 2) - (4x - 11) (2x + 1) = (x - 3) (x + 7)

⇒ (9x² + 6x - 24x - 16) - (8x² + 4x - 22x - 11) = (x² + 7x - 3x - 21)

⇒ (9x² - 18x - 16) - (8x² - 18x - 11) = x² + 4x - 21

⇒ 9x² - 18x - 16 - 8x² + 18x + 11 = x² + 4x - 21

⇒ x² - 5 = x² + 4x - 21

⇒ - 5 = 4x - 21

⇒ 4x = 21 - 5

⇒ 4x = 16

⇒ x = 16/4

⇒ x = 4

∴ the required solution be x = 4

So 9x - 4*9 = 36

Correct Option: 7 Best Solution (2)

Varun   4 years AGO

Solving the given equation we get x=4 and 9x=36
= option (7)

Like? Yes | No (1)  

RAMADURAI NATESAN   4 years AGO

After expanding the bracket on both sides,we get
- 5 =4x - 21 or x = 4 . 9x = 16

Like? Yes | No (2)