Find the circumference of the circles with the following radius: (take π =
22
7 )
(a) 14 cm (b) 28 mm (c) 21 cm

circumfrence of a circle= 2πr

  (a)14 cm                = 2*22/7*14

                                = 88cm

  (b)28cm = 2*22/7*28

                  =176cm

 (c)21cm = 2*22/7*21

                132cm

- 2 + 10x³ - 21x² + 19x - 4

step-by-step explanation:

each term in the second factor is multiplied by each term in the first factor

x²(- 2x² + 4x - 1) - 3x(- 2x² + 4x - 1) + 4(- 2x² + 4x - 1) ← distribute

= - 2 + 4x³ - x² + 6x³ - 12x² + 3x -8x² + 16x - 4

collect like terms

= - 2 + 10x³ - 21x² + 19x - 4 ← in standard form