Answer: To date rocks geologists first give a relative age to a layer of rock at one location. Then they can give the same age to matching layers of rock at other locations. Certain fossils, called index fossils, help geologists match rock to layers.
The answer to this problem is 11 because I did the inverse the inverse of subtraction is addition so I added 7+4 that gave me 11 than I subtracted 11-7 that gave me 4 so x=11