Answer:
a) The correct option is C: 4x
b) The correct option is B: 2x
Step-by-step explanation:
a) Usually when we have a real number multiplying a variable, we do not need to write the multiplication symbol.
So instead of writing:
4×x
We can write:
4x
And this will be equivalent.
Then in this case the correct option is C.
b) We know that if we have the multiplication of A by n, this will be equivalent to add A n times.
Then if we have the sum of A, for example, 4 times, we have:
A + A + A + A
And this can be written as 4*A
In this case, we have the expression x + x.
So we are adding x two times, then this can be written as: 2*x, or, as we said earlier, this also can be written as 2x.
Then the correct option is option B.
Answer: she would catch up with Tom in 1 hour.
Step-by-step explanation:
Let t represent the time it will take for Mary to catch up with Tom.
Tom leaves his boat from a dock and travels at a rate of 25 miles per hour.
Distance = speed × time
Distance travelled by Tom in t hours is
25 × t = 25t
Ten minutes later, Mary leaves the same dock in her speedboat and heads after Tom. Converting 10 minutes to hours, it becomes 10/60 hour
Time spent by Mary is (t - 10/60) hours. If she travels at a rate of 30 miles per hour, it means that the distance that she would travel in
(t - 10/60) hours is
30(t - 10/60)
= 30t - 5
By the time she catches up with Tom, they would have covered the same distance. It means that
25t = 30t - 5
30t - 25t = 5
5t = 5
t = 5/5 = 1 hour
Answer: Choice B. 54degrees
Step-by-step explanation:
Angles 1 4 5 8 are equal and angles 2 3 6 7 are also equal. These two sets of angles of supplementary(you‘d get 180 by adding them).
so
13x+9=180-(5x+9)
by simplifying the equation youll get
18x+18=180
x=9
so angle 7(and therefore angle 6) equals
5*9+9=54
Answer:
x = 2
Step-by-step explanation:
Multiply both sides by (x-5) and expand:
(x+4)/(x-5)*(x-5) = -2(x-5)
x+4 = -2x+10
Subtract 4 from both sides:
x+4-4 = -2x+10-4
x = -2x+6
Add 2x to both sides:
x+2x = -2x+6+2x
3x = 6
Divide both sides by 3:
3x/3 = 6/3
x = 2
