Plz help its due by 1

Solve 2x+y=3 x+y=5 in substitution method

An initial investment of $100 is now valued at $150. the annual interest rate is 5%, compounded continuously. the equation 100e0.05t = 150 represents the situation, where t is the number of years the money has been invested. about how long has the money been invested? use your calculator and round to the nearest whole number. years

If f(x) = 2x + 8 and g(x) = x4, what is (gº)?