Question

10. Let A = 3x - 5x + 7, B = 2x - 8x2 + 9, C = 7+ 5x2 - 3x
Find : (a) A + B - C, (b) A - 2B + C, (c) A + B + 3C


explain the question​

Answer 1

Answer:

 Add the ... we get 5x3+ 3x3 + 3x3- x3- 5x2 + 2x2 - 2x2 - x2- x2 + 6x - 9x + 4x - 9x + x + 7 - 8 - 4 ... ( ii) 4ab-5bc+7ca-3ab+2bc-3ca5ab-3bc+4ca ... Now, required expression = (x2 + 2xy + y2) + (3x2 - 4y2 + 9)

Answer 2

Answer:

(a) Required value of A + B - C is $9 - 13{x}^{2} +3x$

(b) Required value of A - 2B + C is $21 {x}^{2} - 9x - 4$

(c) Required value of A + B + 3C is $7 {x}^{2} - 9x + 37$

Step-by-step explanation:

Given,A = $3x - 5x + 7 = - 2x + 7$

B = $2x - 8 {x}^{2} + 9$

C = $7 + 5 {x}^{2} - 3x$

(a) A + B - C

$= - 2x + 7 + 2x - 8 {x}^{2} + 9 - (7 + 5 {x}^{2} - 3x)$

$= - 2x + 7 + 2x - 8 {x}^{2} + 9 - 7 - 5 {x}^{2} + 3x$

$= - 8 {x}^{2} + 9 - 3x \\ = 9 - 13 {x}^{2} + 3x$

(b)

A - 2B + C

$= - 2x + 7 - 2(2x - 8 {x}^{2} + 9) + (7 + 5 {x}^{2} - 3x)$

$= - 2x + 7 - 4x + 16 {x}^{2} - 18 + 7 + 5 {x}^{2} - 3x$

$= 21 {x}^{2} - 9x - 4$

(c)

A + B + 3C

$= - 2x + 7 + (2x - 8 {x}^{2} + 9) + 3(7 + 5 {x}^{2} - 3x)$

$= - 2x + 7 + 2x - 8 {x}^{2} + 9 + 21 + 15 {x}^{2} - 9x$

$= 7 {x}^{2} - 9x + 37$

This is a problem of Algebra.

Some important Algebra formulas.

(a + b)² = a² + 2ab + b²

(a − b)² = a² − 2ab − b²

(a + b)³ = a³ + 3a²b + 3ab² + b³

(a - b)³ = a³ - 3a²b + 3ab² - b³

a³ + b³ = (a + b)³ − 3ab(a + b)

a³ - b³ = (a -b)³ + 3ab(a - b)

a² − b² = (a + b)(a − b)

a² + b² = (a + b)² − 2ab

a² + b² = (a − b)² + 2ab

a³ − b³ = (a − b)(a² + ab + b²)

a³ + b³ = (a + b)(a² − ab + b²)

Know more about Algebra,

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