B is your answer
The perimeter of a rectangle is2l + 2wThis has to be less than 30 because she has less than 30 inches of wood altogether.
Expand the following:
(5 a + b/5)^2
(5 a + b/5) (5 a + b/5) = (5 a) (5 a) + (5 a) (b/5) + (b/5) (5 a) + (b/5) (b/5):
5×5 a a + (5 a b)/5 + (5 b a)/5 + (b b)/(5×5)
(5 a b)/5 = 5/5×a b = a b:
5×5 a a + a b + (5 b a)/5 + (b b)/(5×5)
(b×5 a)/5 = 5/5×b a = b a:
5×5 a a + a b + b a + (b b)/(5×5)
Combine powers. (b b)/(5×5) = (b^(1 + 1))/(5×5):
5×5 a a + a b + b a + (b^(1 + 1))/(5×5)
1 + 1 = 2:
5×5 a a + a b + b a + (b^2/5)/5
5 a×5 a = 5×5 a^2:
5×5 a^2 + a b + b a + (b^2/5)/5
5×5 = 25:
Answer: 25 a^2 + a b + b a + (b^2/5)/5
9514 1404 393
Answer:
- northbound: 2.5 hours
- southbound: 1.5 hours
Step-by-step explanation:
When the second train leaves the station, the trains are already 63 miles apart. The rate of increase of their separation is (57 +63) = 120 miles per hour. The remaining 243-63 = 180 miles of separation will be achieved in ...
(180 mi)/(120 mi/h) = 1.5 h
The northbound train will have traveled 2.5 hours; the southbound train will have traveled 1.5 hours when the trains are 243 miles apart.
An ordered pair (x,y) is a solution to a system of equations if it makes all the equations true.
Let's check whether (–1, 5) makes the equations true.
Plugging –1 in the first equation for x and 5 in for y, we get
–1 + 5 = 4: TRUE
Plugging –1 in the second equation for x and 5 in for y, we get
–1 – 5 = –6: TRUE
Since it makes both the equations true, it's a solution to the system of equations. So the answer choice is D, the 4th one.
