To pass a course with a b grade, a student must have an average of 80 or greater. a student’s grades on three tests are 73, 86, and 78. find what score the student must get on the next test to get a b average or better. what grade must the student get? or greater.

To do this you need to know how to find an average. You add all of the values together and divide by the number of values you have. For this problem, we are missing one of the values so we will just call it x. Now we can make the equation and solve:

(73+86+78+x)/4=80

73+86+78+x=320

237+x=320

83=x

They need and 83% on their test to get a B overall.

set each factor equal to 0

4x-3 = 0

2x-1 = 0

solve for x.

4x-3=0

4x=3

x= 3/4

solve for x. 

2x-1= 0

2x= 1

x= 1/2

your answer should be 1/2 is less than or equal to x and 3/4 is greater than or equal to x

you didn't post any answer choices, so its not 100% clear what your teacher is looking for

however, log(15/7) is equivalent to log(15) - log(7)

i'm using the rule log(x/y) = log(x) - log(y)