Answer:
a. 2x + 4
Step-by-step explanation:
Four more than twice a number
Let x = unknown number
Four more than twice of x
Twice of x can be written as 2x
Four more than 2x
Four more can be written as + 4
We get 2x + 4
Answer:
y=-7x+48 slope would be -7
Step-by-step explanation:
Used a Regression Calculator
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Let b and s be the velocity of the boat and stream respectively....
3(b-s)=27
b-s=9
b=9+s we will use this in the second equation....
2(b+s)=30
b+s=15, now use b found above in this to get:
9+s+s=15
2s+9=15
2s=6
s=3, and since from earlier b-s=9, b=9+s so
b=12
So the speed of the boat is 12mph and the stream is 3 mph
Answer:
D. 9990 possible combinations
Step-by-step explanation:
The first digit has 10 choices (can be all of them), the second digit also has 10 choices. The third and fourth digits also have 10 choices.
Multiply them together you get 10*10*10*10 = 10000 possible combinations.
But since all 4 characters cannot be the same, we subtract 10 from 10000 (there are 10 combinations which the 4 characters are the same: 1111, 2222, 3333, 4444, 5555, 6666, 7777, 8888, 9999, and 0000) and we get 9990.