Grade 9 Algebraic Identities

(x - 8) ( x - 8) = ______

• x² - 64
• x² + 64
• x² - 16x + 64
• x² + 16x + 64

Expand (4x − 5)(4x + 5).

• 4x² − 25

• 4x² + 25

• 16x² + 25

• 16x² − 25

(x² - y²) × (x² + y²) = ______

• 2x² + 2y²
• x⁴ - y⁴
• x⁴ + y⁴
• 2x⁴

(a-b)^3

• a^3 -b^3-3ab(a-b)

• a^3 + b^3-3ab(a-b)

• a^3 - b^3+3ab(a-b)

• a^3 - b^3-3ab(a+b)

 $x^{3\ }-y^3\ =$  

•  $\left(x\ -y\right)\left(x^2\ -xy\ +y^2\right)$  

•  $\left(x\ -\ y\right)\left(x^2\ +\ xy\ +y^2\right)$  

• (x + y) ( x - y)

 $\left(a\ +b\right)^3=$  

•  $a^3\ +b^3\ +3\ ab\ +3\ b^2a\$  

•  $a^3\ +b^3\ +3\ a^2\ b\ +3\ a\ b^2$  

•  $a^2\ +b^2\ +3\ a^2\ b\ +3\ a\ b^2$  

If a + b = 5 and ab = 6, find a² + b².

• 13
• 12
• 10
• 11

product of 51 X 49 find using the identity -------------- and product is --------

• ( a-b) (a + b) = a² -b² , 2499

• (x + a) ( x + b ) = x² + (a + b) x ab , 2499

• (a+b)² = a² + 2ab + b² , 2499

• (a - b)² = a² - 2ab + b² , 2499

 $\left(\frac{2m}{3}\ +\ \frac{3n}{2}\right)^2$   is

•  $\frac{4m}{2}+2mn\ +\ \frac{9n}{4}$  

•  $\frac{4m^2}{2}\ +\ 2mn\ +\ \frac{9n^2}{4}$  

•  $\frac{4m^2}{9}+\ 2mn\ +\ \frac{9n^2}{4}$  

•  $\frac{4m^2}{9}-\ 2mn\ \ +\ \frac{9n^2}{4}$