How do you do this? 20 points

a) i) 9:25

ii) 27:125

b) i) 7:9

ii) 343:729

Step-by-step explanation:

Ratio of areas = (ratio of sides)²

= 3² : 5² = 9 : 25

Ratio of volumes = (ratio of sides)³

= 3³ : 5³ = 27 : 125

49 : 81 = ratio of areas

Ratio of sides = 49^½ : 81^½

= 7 : 9

Ratio of volumes = (ratio of sides)³

7³ : 9³ = 343 : 729

{x = -1/2 ,   y = -1

step-by-step explanation:

solve the following system:

{2 x + y = -2

{10 x - 3 y = -2

in the first equation, look to solve for y:

{2 x + y = -2

{10 x - 3 y = -2

subtract 2 x from both sides:

{y = -2 x - 2

{10 x - 3 y = -2

substitute y = -2 x - 2 into the second equation:

{y = -2 x - 2

{10 x - 3 (-2 x - 2) = -2

10 x - 3 (-2 x - 2) = (6 x + 6) + 10 x = 16 x + 6:

{y = -2 x - 2

{16 x + 6 = -2

in the second equation, look to solve for x:

{y = -2 x - 2

{16 x + 6 = -2

subtract 6 from both sides:

{y = -2 x - 2

{16 x = -8

divide both sides by 16:

{y = -2 x - 2

{x = -1/2

substitute x = -1/2 into the first equation:

{y = -1

{x = -1/2

collect results in alphabetical order:

answer:   {x = -1/2 ,   y = -1