What is 5^4 times 5^7

The graph shows the function f(x) = (2.5)x was horizontally translated left by a value of h to get the function g(x) = (2.5)x–h.

Solve the equation by completing the square. x^2+2x=17

The half-life of a certain material is 0.004 second. approximately how much of a 20-gram sample will be left after 0.016 second? a. 5 grams b. 16 grams c. 0.32 gram d. 1.25 grams