Answer:
x+y=15
Step-by-step explanation:
Given equation of 
Differentiating both side 

It passes through the point (12,3) so

So equation of tangent passing through (12,3) is
as 
So x+y =15 will be the equation of tangent which passes though the point (12,3)
Answer:
10.5 inches
Step-by-step explanation:
The length of the longest diagonal is across two opposite points of the solid, namely
L = sqrt ( 6^2 + 5^2 + 7^2)
= sqrt (36+25+49)
= sqrt(110)
= 10.5"
It is the first one. Three times a number means 3x. The sum of 3x and 7 is 3x + 7 because sum means additions. And 3x + 7 is greater than four times the number which is 4x and greater than is this symbol >. So 3x + 7 > 4x