let's convert the mixed fraction to improper fraction, and then check.

(71+x)/2=78
71+x=156
x=85
Th student needs to score a min of 85
What's the question? what are you asking?
Answer:
11
Step-by-step explanation:
-4x + 7 ; x = -1
-4x (-1) + 7
4 + 7 = 11
A way to add fractions that always works is to multiply each numerator by the denominator of the other, then express the sum of products over the product of the denominators.

Here, you have
The sum is -1 1/12