You already know that y equals -4. It says that x equals 3, so multiply the -4 by 3 and because it has a negative number and a positive number it will equal -12. Remember anytime you see a letter after a number it means multiply. The complete problem should be -10 because 2 is a whole number you subtract it from -12. Hope that helped you out some.
LORAN follows an hyperbolic path.
The equation of the hyperbola is: 
The coordinates are given as:

The center of the hyperbola is

The distance from the center to the focal points is given as:

Square both sides

The distance from the receiver to the transmitters is given as:

Divide both sides by 2

Square both sides

We have:

This gives

The equation of an hyperbola is:

So, we have:


Hence, the equation of the hyperbola is: 
Read more about hyperbolas at:
brainly.com/question/15697124
Total surface area of cylinder :
[(22/7)(7)²] × 2 ( area for 2 circles )
+
[ 2(22/7)(7) ] ×12 ( circumference of circle × height )
=
836 cm²
i hope my solution helps :))