A parabola has a focus of (–10, 2) and a directrix of y = 4. What is the parabola’s equation? a) y = 1/4 (x - 10)^2 - 3
b) y = 1/4 (x + 10)^2 + 3
c) y = - 1/4 (x - 10)^2 - 3
d) y = - 1/4 (x + 10)^2 + 3

all three statements are true

step-by-step explanation:

a shipping fee of 5% is charged online with every item purchased online

first let's just take each option and calculate them based on this, to see if the answers matched

keith buys a 40 dollar book

40 x 0.05 = 2

therefore there will be a two dollar fee on keith's book

40 + 2 =42

the first statement is true

a chair costs $80

80 x 0.05 = 4

80 + 4 = 84

the second statement is true

george buys a 20 dollar calculator

20 x 0.05 = 1

20 + 1 = 21

the third statements are true

all three statements are true

let x and 400 - x be the two numbers.  

==> 0.80x + 0.85(400 - x) = 400 - 68 from the statement of the problem.  

< ==> 0.80x + 0.85(400 - x) = 400 - 68  

==> 340 - 0.05x = 332  

< ==> -0.05x = -8 ==> x = 160, the first number ==> 400 - x = 240, the second number.

w< 4

step-by-step explanation:

the answer is about 24 dollars