Answer:
The answer is 9
Step-by-step explanation:
The answer is 9
3x + 6 = -1 - 3 + 4x
Combine like terms on the right side.
3x + 6 = -4 + 4x
Add 4 to both sides.
3x + 10 = 4x
Subtract 3x from both sides.
10 = x
The equation has one solution (10).
They are both isosceles triangles
Answer:
x = 17 and y = 37
Step-by-step explanation:
Let the numbers be x and y.
y = 3 + 2x
xy = 629
substituting y in the second equation we get
x(3+2x) = 629
3x + 2
= 629
2
+ 3x - 629 = 0
Solving a quadratic equation by using its formula:
x = [-3 ±√(9-4(2)(-629)] / 4
x = [-3 ± √5041] / 4
x = [-3 ± 71] / 4
x = 17 and 
Ignore the negative number in x and just use x = 17 in the first equation we get
y = 3 + 2(17) = 37
Answer:
5.78% probability that exactly 2 of them use their smartphones in meetings or classes.
Step-by-step explanation:
For each adult, there are only two possible outcomes. Either they use their smarthphone in meetings or classes, or they do not. The probability of an adult using their smartphone on meetings or classes is independent of other adults. So we use the binomial probability distribution to solve this question.
Binomial probability distribution
The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.

In which
is the number of different combinations of x objects from a set of n elements, given by the following formula.

And p is the probability of X happening.
63% use them in meetings or classes.
This means that 
7 adult smartphone users are randomly selected
This means that 
Find the probability that exactly 2 of them use their smartphones in meetings or classes.
This is P(X = 2).


5.78% probability that exactly 2 of them use their smartphones in meetings or classes.