Answer:
12
+ 6y
Step-by-step explanation:
Answer:
X = 6
Step-by-step explanation:
1 pencil + 1 eraser = $1.10
Pencil cost $1 more than the eraser.
⇒ If we take away $1 from the total, both the pencil and the eraser will cost the same.
⇒ $1.10 - $1.00 = $0.10
Divide by 2 to find the cost of the eraser.
⇒$0.10 ÷ 2 = $0.05
Find the cost of the pencil, which is $1 more than the eraser.
⇒ $0.05 + $1 = $1.05
Answer: The eraser costs $0.05
So x + y = 45, and 4x + 5y = 195. Get y by itself. Subtract x from both sides in the first equation to get y = 45 -x, and subtract 4x from the second equation to get 5y = 195 - 4x. Divide by 5 to both sides to get y = 39 - 4/5x. 39 - 4/5x = 45 - x. Add x to both sides to get 39 - 1/5x = 45. Subtract 39 from both sides to get -1/5x = 6. Divide by -1/5 to get x = -30, or 30. In the first equation, do 30 + y = 45. Subtract 30 from both sides to get y = 15. Check. 4(30) + 15(5) = 195, or 120 + 75 = 195.
5π/12 = (5 · 180°) : 12 = 75°
cos 75° = cos ( 45° + 30° )= cos 45° cos 30° - sin 45° sin 30° =
=√2/2 * √3/2 - √2/2 * 1/2 =
=(2.4495 - 1.4142): 4 = 0.258825
