What are the three basic types of positive displacement pumps.

a) reciprocating pump

b) rotary pump

c) linear pump

Explanation:

Positive displacement pump has enlarged  cavity on the suction side and decreasing cavity on the discharge side and in  positive displacement pump

the amount of fluid captured and inside and then discharged is same.

There are three type of positive displacement pump

a) reciprocating pump is the pump which two valve during suction outlet valve is closed and  for delivery the inlet valve is closed and pump is used for discharge

b) rotary pump fluid move with the help of rotary the rotation of rotary displaces water.

c) linear pump is the pump in which displacement is linear rope and chain pump is example of this type of pump.

x+2 because it just doubles hon so the pattern can actually tell you the expression.

so for example,

if x=2 then 2+2 is 4

if x=4 then 4+4 is 8

and so on and so forth.

i really hope that this makes sense and you out in a way hon: )