18 - 2[x + (x-5)]
First I would get rid of the inside parenthesis by distributing the + to everything inside and end up with;
18 - 2[x + x - 5]
Then I'd combine like terms inside the brackets
18 - 2[2x - 5]
Then I'd multiply what is inside the brackets by the -2
18 - 4x + 10
I'd combine like terms and end up with:
28 - 4x......or rewritten as -4x + 28
Cost : Selling Price
175 : 300
175 ÷ 25 : 300 ÷ 25
7 : 12
1) we calculte the driver´s unit rate of speed.
s=speed
d=distance
t=time.
s=d/t
45 miles------------------3/4 hour
x----------------------------- 1 hour
x=(45 miles * 1 hour) / (3/4 hour)=60 miles.
speed or rate=60 miles / 1 hour.
2)we calculate the distance traveled at 1.25 hour.
distance=rate * time
distance=(60 miles /1 hour) * 1.25 hour=75 miles.
Answer: the driver would´t go late, because, the distance is 65 miles, and he can travel 75 miles if he drive with that speed .
Answer:
d = 16.5
Step-by-step explanation:
Add -35.5 to both sides of the equation, then simplify.
... d + 35.5 - 35.5 = 52 - 35.5
... d + 0 = 16.5
... d = 16.5
_____
In general, if something unwanted is added, adding the opposite will undo that operation.
Answer:
343 : 729
Step-by-step explanation:
A cube is made up of 6 square faces. If each face has a side length of a, we can find the surface area of that cube with the formula 
, since we'll have 6 faces with area a². Let's call the edge length of the first cube a and the edge length of the second cube b. The ratio between their surface areas is then 6a² : 6b², or simply a² : b². If we compare this to our given ratio 49 : 81, we can see that a² = 49 and b² = 81, or, square rooting both equations, a = 7 and b = 9.
The volume of a cube with a side length a is a³, so the ratio between our cubes here must be a³ : b³. Using the values for a and b we just found, this ratio becomes 7³ : 9³, which we can simplify to 343 : 729.
