Answer: A
Step-by-step explanation:
points
Answer:
y= -2x+1
Step-by-step explanation:
y=mx+b
y= -2x +b
3= -2(1) +b
3= -2 +b
b=1
y= -2x+1
The answer is B because every time Nelson mows a lawn, he will earn $15 each.
You figure out how long it would take a car traveling at 25 mph
to cover 360 ft. Any driver who does it in less time is speeding.
(25 mi/hr) · (5,280 ft/mile) · (1 hr / 3,600 sec)
= (25 · 5280 / 3600) ft/sec = (36 and 2/3) feet per second.
To cover 360 ft at 25 mph, it would take
360 ft / (36 and 2/3 ft/sec) = 9.82 seconds .
Anybody who covers the 360 feet in less than 9.82 seconds
is moving faster than 25 mph.
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If you're interested, here's how to do it in the other direction:
Let's say a car covers the 360 feet in ' S ' seconds.
What's the speed of the car ?
(360 ft / S sec) · (1 mile / 5280 feet) · (3600 sec/hour)
= (360 · 3600) / (S · 5280) mile/hour
= 245.5 / S miles per hour .
The teacher timed one car crossing both strips in 7.0 seconds.
How fast was that car traveling ?
245.5 / 7.0 = 35.1 miles per hour
Another teacher timed another car that took 9.82 seconds to cross
both strips. How fast was this car traveling ?
245.5 / 9.82 = 25 miles per hour
Answer:
x = - 1 ± 2i
Step-by-step explanation:
we can use the discriminant b² - 4ac to determine the nature of the roots
• If b² - 4ac > , roots are real and distinct
• If b² - 4ac = 0, roots are real and equal
• If b² - ac < 0, roots are not real
for x² + 2x + 5 = 0
with a = 1, b = 2 and c = 5, then
b² - 4ac = 2² - (4 × 1 × 5 ) = 4 - 20 = - 16
since b² - 4ac < 0 there are 2 complex roots
using the quadratic formula to calculate the roots
x = ( - 2 ± 
) / 2
= (- 2 ± 4i ) / 2 = - 1 ± 2i
