Answer:
15 mph
Step-by-step explanation:
75/5=15
Expand the brackets: x²+5x+6=kx+2. So x²+(5-k)x=-4.
To complete the square on the left we add ((5-k)/2)² to each side:
(x+(5-k)/2)²=((5-k)/2)²-4.
Take a look at the right hand side: when this is zero we have equal roots:
((5-k)/2)²=4, (5-k)/2=±2, 5-k=±4, k=5∓4, giving us k=1 or 9.
(5-k)/2 is 2 or -2. So if k=9, (x-2)²=0. And x=2 is the positive root.
First you add 3 twice to both sides of the swimming pool
12 + 6 = 18
15 + 6 = 21
The perimeter is the sum of all sides therefore
18 + 18 + 21 + 21 = 78
The answer is A
