Question

Short Answer Questions (2marks each)
7. Factorise x3 - X.
8. Factorise y2 -10y +21
9.Simplify and find the value of,
x(x - 2) + 3 for x= (-1)
10.Find the sum of 5xy2 - 2 and 4 + xy2
11. Expand using identity ( x + 2p2)2
12. Using identity find the value of 297 x 303
13.Divide : 10x2 - X-3
(2x +1)​

Answer 1

Answer:

${x}^{3} - x \\ x ({x}^{2} - 1)$

${y}^{2} - 10y + 21 \\ {y}^{2} - 3y - 7y + 21 \\ y(y - 3) - 7(y - 3) \\ (y - 7) \: (y - 3) = 0 \\ y = 7 \: \: y = 3$

$x(x - 2) + 3 \: \: \: \: \: x = - 1 \\ - 1( - 1 - 2) + 3 = \\ - 1( - 3) + 3 = \\ 3 + 3 = 6$

$5x {y}^{2} - 2 \: and \: x {y}^{2} + 4 \\ 5x {y}^{2} + x {y}^{2} - 2 + 4 \\ 6x {y}^{2} + 2 \\ 2(3x {y}^{2} + 1)$

$10 {x}^{2} - x - 3 \: \: \: \: \: \: \: (2x + 1) \: \: \: \: 2x = - 1 \: \: x = \frac{ - 1}{2} \\ 10( { \frac{ - 1}{2} })^{2} - \frac{ - 1}{2} - 3 \\ 10 \frac{1}{4} + \frac{1}{2} - 3 \\ \frac{5}{2} + \frac{1}{2} - 3 = 0 \\ 3 - 3 = 0$