A student has gotten the following grades on his tests. What is the minimum grade he must get on the last test in order to have an average of 80?
73. 87, 85, 70

85%

Step-by-step explanation:

To find his average you add all his scores together and divide it by the number of scores there are. So 73+87+85+70+85=80, and that will be his average if he gets an 85% on his last test.

x =-.20752

step-by-step explanation:

4^(x+2)=12

4^(x+2)=12

take the log base 4 on each side

log 4 (4^(x+2) = log 4(12)

we know log b(a^y) = y log b (a)

(x+2) log 4(4) = log 4 (12)

x+2 = log 4 (12)

we know   logb c = loga c/loga b

we want to convert to base 10   so a = 10

by default, we do not write the 10   c = 4   and b = 10

log4 10 = log 12/log 4

log4 10 = log 12/ log 4

x+2 = log 12/ log 4

subtract 2 from each side

x +2 -2 = log 12/ log 4 -2

x = 1.79248125 -2

x =-.20752