Question

From
(i) p³ − 4 + 3p², take away 5p² − 3p³ + p − 6
(ii) 7 + x − x², take away 9 + x + 3x² + 7x³
(iii) 1 − 5y², take away y³ + 7y² + y + 1
(iv) x³ − 5x² + 3x + 1, take away 6x² − 4x³ + 5 + 3x

Answer 1

(i) Required expression = (p³ - 4 + 3p²) - (5p² - 3p³ + p - 6)
= p³ - 4 + 3p² - 5p² + 3p³ - p + 6
= p³ + 3p³ + 3p² - 5p²- p - 4+ 6
= 4p³ - 2p² - p + 2

(ii) Required expression = (7 + x - x²) - (9 + x + 3x² + 7x³)
= 7 + x - x² - 9 - x - 3x² - 7x³
= - 7x³- x² - 3x² + 7 - 9
= - 7x³ - 4x² - 2

(iii) Required expression = (1 - 5y²) - (y³+ 7y² + y + 1)
= 1 - 5y² - y³ - 7y² - y - 1
= - y³- 5y² - 7y² - y
= - y³- 12y² - y

(iv) Required expression = (x³ - 5x² + 3x + 1) - (6x² - 4x³ + 5 +3x)
= x³ - 5x² + 3x + 1 - 6x² + 4x³ - 5 - 3x
= x³ + 4x³ - 5x² - 6x² + 1 - 5
= 5x³ - 11x² - 4