simplify

Question

(8*10^7)(7*10^4)
i think it's 5.6*10^10

simplify
(3*10^6)(8*10^-4)
i think it's 2.4*10^3

Astronomers measure large distances in light-years. One light-year 5.88*10^12 mi
Star is 9.8*10^1 light years from Earth
in scientific notation how many miles
I think it's 5.88*10^12 miles

Radio signals travel 3x10^8 mi/sec
How long would it take to travel from satellite to Earth surface if orbiting at height of 4.2*10^7 mi
I think it's 1.26*10^15 seconds

simplify
(4/7y^5)^2
I think it's 8/14y^10

(t^4/10y^4)^-4
I think it's -40t^16/4y^16

Does the rule -3(4^x) represent an exponential function?
I think yes.

3,300.00 principal 4% interest compounded annually after 3 years what's the balance

i think it's $3,712.05

3,500.00 principal 3% interest compounded semiannually. After 20 years what's the balance.

i think it's $6,349.06

A car costs $25,750.00 and decreases value 20% per year
How much worth after 5 years?

I think it's $8,240.00

An investment account earns 4% per year compounded annually. If the initial investment was 4,000.00, how much is in the account after 3 years? Round your answer to the nearest dollar.

I think it's somewhere around $4,520

Answer 1

simplify
(8*10^7)(7*10^4)
i think it's 5.6*10^10 < --- incorrect

simplify
(3*10^6)(8*10^-4)
i think it's 2.4*10^3 < --- correct

Astronomers measure large distances in light-years. One light-year 5.88*10^12 mi
Star is 9.8*10^1 light years from Earth
in scientific notation how many miles
I think it's 5.88*10^12 miles < --- incorrect

Radio signals travel 3x10^8 mi/sec
How long would it take to travel from satellite to Earth surface if orbiting at height of 4.2*10^7 mi
I think it's 1.26*10^15 seconds < --- incorrect
< --- ridiculous question, no orbit is that far away, the sun is only 150 million miles away

simplify
(4/7y^5)^2
I think it's 8/14y^10 < --- incorrect

(t^4/10y^4)^-4
I think it's -40t^16/4y^16 < --- incorrect

Does the rule -3(4^x) represent an exponential function?
I think yes. < --- correct

3,300.00 principal 4% interest compounded annually after 3 years what's the balance

i think it's $3,712.05 < --- correct

3,500.00 principal 3% interest compounded semiannually. After 20 years what's the balance.

i think it's $6,349.06 < --- correct

A car costs $25,750.00 and decreases value 20% per year
How much worth after 5 years?

I think it's $8,240.00 < --- incorrect

An investment account earns 4% per year compounded annually. If the initial investment was 4,000.00, how much is in the account after 3 years? Round your answer to the nearest dollar.

I think it's somewhere around $4,520< --- incorrect

Answer 2

I need help as well.