Answer:
Step-by-step explanation:
Use FOIL method
F -> First
O Outside
I inside
L Last
(a - b)(a + 2b)= a*a + a *2b + (-b)*a + (-b)*2b
= a² + <u>2ab - ab</u> - 2b²
Combine like terms
= a² + ab - 2b²
19=1-5h-4h
19-1=-5h-4h
18=-9h
18/-9=h
h=-0.5
Answer:
2 1/2 rolls of ham
Step-by-step explanation:
Break down the question. 1/4 is for 1 slice of cheese. So if she is going to use 1 1/4 now. That means that would be equal to 5 slices of cheese. Now look at the ham. It allows you to start with 1/2 rolls of ham. To make it equal to the 5 slices of cheese. You will do add 1/2 together 5 times. Adding 1/2 and 1/2 is 1. So if you do that another two times. Its now 2. Add one more 1/2 now you have 2 1/2.
Answer:
3/5
Step-by-step explanation:
We need to use the trig identity that cos(2A) = cos²A - sin²A, where A is an angle. In this case, A is ∠ABC. Essentially, we want to find cos∠ABC and sin∠ABC to solve this problem.
Cosine is adjacent ÷ hypotenuse. Here, the adjacent side of ∠ABC is side BC, which is 4 units. The hypotenuse is 2√5. So, cos∠ABC = 4/2√5 = 2/√5.
Sine is opposite ÷ hypotenuse. Here, the opposite side of ∠ABC is side AC, which is 2 units. The hypotenuse is still 2√5. So sin∠ABC = 2/2√5 = 1/√5.
Now, cos²∠ABC = (cos∠ABC)² = (2/√5)² = 4/5.
sin²∠ABC = (sin∠ABC)² = (1/√5)² = 1/5
Then cos(2∠ABC) = 4/5 - 1/5 = 3/5.
