Question

o factorise
9x² - y2
16

• Use the formula to find value
54846
3
find total surface area of cube
it side is 12 cm
a
find diameter and circumfered
if radias is 14cm.
eCAB- 10cm
and L(BO)- 20 CM
find e CAC) = ?​

Answer 1

(1)

$9 {x}^{2} - 16 {y}^{2} \\ \\ = > {(3x)}^{2} - {(4y)}^{2} \\ \\ = > (3x + 4y)(3x - 4y)$

(2) Total surface area of cube = 6(side)^2

$6 \times {12}^{2} = 6 \times 144 = 864$

So, the TSA of cube will be 864 cm^2✔

(3) Radius = Diameter/2 = 14/2 = 7 cm. ✔

Circumference of circle = 2πr

$= > 2 \times \frac{22}{7} \times 7 = 44$

So, the circumference of circle will be 44 cm. ✔