Help me with these few questions!

Question

1: When a number is decreased by 30% of​ itself, the result is 14. What is the​ number?

2: One number exceeds another by 9. The sum of the numbers is 63. What are the​ numbers?

3:A new car worth ​$30,000 is depreciating in value by ​$3,000 per year. Complete parts a. through b. below.

Write a formula that models the​ car's value,​ y, in​ dollars, after x years.

y=

4: After a 70% ​reduction, you purchase a new washing machine on sale for ​$210. What was the original price of the washing machine​?

5: A rectangular athletic field is twice as long as it is wide. If the perimeter of the athletic field is 96 ​yards, what are its​ dimensions?

6: Solve the formula for the specified variable. v= kz for k

7: Solve the formula for the specified variable. K=mc^2 for m

Answer 1

x -.3x = 14

.7x = 14

x =14/.7 = 20

30% of 20 = 6. 20-6 = 14

x-y=9

x+y=63

2x = 72

x = 36

y =27

y= 30,000 -3,000x

70% reduction to $210 original price = P, .3P=210, P= 210/.3 = $700. 70% of 700 = 490. 700-490 = 210

P=96 = 2L+2W = 2(2W)+2W = 6W

W = 96/6 = 16 yds

L= 32 yds

v=kz

k= v/z

K=mc^2

m=K/c^2