H(10) is the altitude of a hot air balloon overtime after 10 minutes. In order to find h(10)'s value, you just have to substitute 10 as t in the equation. h(10) and h(t) represents the value of y in a linear equation. So pretty much: h(10)= 210 - 15(10). If calculated correctly, h(10)=60.
Sample response: t represents time, which is the input of the function, so we know that 10 is the time in minutes. h(t) represents the altitude, which is the output of the function after time, t. So, we need to substitute 10 into 210 – 15t in place of t. Simplifying 210 – 15(10), we get that 60 is the altitude in feet. So, after 10 minutes, the hot air balloon is at 60 feet.