Answer:
Both answers will give an area of 2400 ft2
but with x=60 we have lawn dimensions -60 ft by -40 ft so this is out
x = 10 ft width for the sidewalk
Check: New lawn dimensions
(80-2x)(60-2x) = 60(40) = 2400 ft^2
Step-by-step explanation:
Draw a diagram:
We have a rectangle inside a rectangle.
The larger outside rectangle is the original lawn: 80ft by 60 ft with area 4800 ft2
The smaller inside rectangle is (80-2x)by(60-2x) where x is width of the new sidewalk.
Area of new lawn is 2400 ft^2
(80-2x)(60-2x) = 2400
4800 - 160x - 120x + 4x2 = 2400
4x2 - 280x + 2400 = 0
Factor out a 4
x2 - 70x + 600 = 0
(x-60)(x-10) = 0
x = 60 ft or x = 10 ft
Answer:
613.6
Step-by-step explanation:
Complex numbers emerge when you take the square root of a negative number, since the imaginary unit is defined by the relation , which implies
The only option involving the square root of a negative number is the last one.
Answer:
Step-by-step explanation:
[(2 hours)/(1 day)](14 days)=(18+x)hours
Let's note that the unit of day is in the numerator and denominator. It cancels
[(2 hours)/(1 day)](14 days)=(18 hours)+(x hours)
(2 hours)(14)=(18+x)hours
Let's note that the unit of hours is in the numerators of both sides of the equation. It cancels
(2 hours)(14)=(18+x)hours
(2)(14)=18+x
28=18+x
10=x
HE WILL HAVE TO STUDY 10 HOURS.
Answer: We have 30 pump-hours needed to pump 40000 L
so x/30 = 60000/40000 , where x is the number of pump-hours
x = 45
pump-hours = 45
if pumps = 9
hours = 5
Step-by-step explanation: