Answer:
13x-4
Step-by-step explanation:
MO=7x-4
NO=6x
MO+NO=?
7x-4+6x=13x-4
10x+25 (expressions don't have equal signs)
Answer:
correct option is C) 2.8
Step-by-step explanation:
given data
string vibrates form = 8 loops
in water loop formed = 10 loops
solution
we consider mass of stone = m
string length = l
frequency of tuning = f
volume = v
density of stone =
case (1)
when 8 loop form with 2 adjacent node is
so here
..............1

and we know velocity is express as
velocity = frequency × wavelength .....................2
= f ×
here tension = mg
so
= f ×
..........................3
and
case (2)
when 8 loop form with 2 adjacent node is
..............4

when block is immersed
equilibrium eq will be
Tenion + force of buoyancy = mg
T + v ×
× g = mg
and
T = v ×
- v ×
× g
from equation 2
f ×
= f ×
.......................5
now we divide eq 5 by the eq 3

solve irt we get

so
relative density 
relative density = 2.78 ≈ 2.8
so correct option is C) 2.8
15,2,31,13
Answer:
Solution given:a number that is divisible only by itself and 1 (e.g. 2, 3, 5, 7, 11).
now
all prime numbers are:
15,2,31,13