21. Use the construction in the proof of

At the beginning of an environmental study, ad forest covered an area of $1500k{m}^2$.Since then, this area has decreased by 4.25% each year.Let t be the number of years since the start of the study.Let y be the area that the forest covers in $k{m}^2$. 
Write an exponential function showing relationship between y and t.

Some friends tell you that they paid $25,000 down on a new house and are to pay $525 per month for 30 years. If interest is 7.8% compounded monthly, what was the selling price of the house? How much interest will they pay in 30 years?

t e^-4t sin3t

Find all whole number solutions of the congruence equation. 
3x ≡ 8 mod 11

Use a direct proof to show that the product of two rational numbers is rational.

Y=2(x-) (x+1) 

what is vertex

axis of symmetry

x-intercept(s)

y-intercept

Stairs- Each step of a set of stairs has a tread depth of 11.5 inches and a riser height of 6.5 inches. What is the slope of the set of stairs?

A ball of mass 5 kg is attached to a string of length 10 cm, forming a pendulum. If the string is raised horizontally as shown and released from point A, then what is the v

assume that the random variable Xand Y have the joint pdf f(x,y)=1/2x^3

5=20 mod 4 true or false answer 

5x−4y=

• $-12$−12

Pets Plus and Pet Planet are having a sale on the same aquarium. At Pets Plus the aquarium is on sale for 30% off the original price and at Pet Planet it is discounted by 25%.

If the sales tax rate is 8%, which store has the lower sale price?

, 1 of 1.Select ChoicePets PlusPet Planet has the lower sale price.

Part B

Fill in the blank question.

How much will you save by buying the aquarium at the store with the lower sale price? Round to the nearest cent.

$

Prove that if x is and irrational number and x>0 then route over x is also irrational 

A small object has charge Q. Charge q is removed from it and placed on a second small object. The two objects are placed 1 m apart. For the force that each object exerts on the other to be a maximum. q should be: A. 2Q B. Q C. Q/2 D. Q/4 E. 0