Answer:
I´m not a Mr. Beast fan but the answer is 4. 4*12 (which is the sum of 7 and 5) = 48
The equation is (7+5)x=48
This simplified is 126x so that is equivalent to this expression
I believe it is 3x+21 but i could be wrong :/ my explaination is -3 • -X would be +3x because it was distributed and -3 • -7 would be +21
Answer:

Step-by-step explanation:
The multiplicative inverse of a number n is 
The product of the number and its multiplicative inverse = 1
n ×
= 1
Thus the multiplicative inverse of
is
= 