Answer:
Step-by-step explanation
Hello!
3x/4 + 6=42
3x/4=42-6 = 36
3x = 36*4
3x = 144
x= 144/3 =48
3/4 of 48 = (48*3) / 4 =36
36+6=42
the original number is 48
Answer:
-1
Step-by-step explanation:
The required relation is ...
7n = n^2 -8
0 = n^2 -7n -8 . . . . put in standard form
0 = (n -8)(n +1) . . . . factor
Solutions are n=8 and n=-1.
The negative solution is -1.
Answer:
x = 5m/s
Step-by-step explanation:
Distance flying out = 12 km (headwind)
Distance flying back = 12 km (tailwind)
total distance = 12 + 12 =24 km
wind speed = 1km/h
speed going out (with headwind) = (x - 1) km/h
speed coming back (with tailwind) = (x + 1) km/h
Time taken to go out = distance going out / speed going out
= 12 / (x-1)
Time taken to come back = distance coming back / speed coming back
= 12 / (x+1)
total time = time taken to go out + time taken to come back
5 =[ 12/(x-1) ] + [ 12/(x-1)]
expanding this, we will get
5x² - 24x - 5 = 0
solving quadratic equation, we will get
x = -1/5 (impossible because speed cannot be negative)
or
x = 5 (answer)
Answer:
36
Step-by-step explanation:
