THE SUM OF A NUMBER, X
AND 9 is 21.
SOLVE FOR X.

X + 9 = 21

Isolate the variable, meaning getting rid of the constants

-9         -9

X = 12

12

Step-by-step explanation:

To get the answer 12 you must:

Subtract 21 - 9

That would get you your answer.

or

step-by-step explanation:

we need to solve for 'x' the following equation:  

we have that:

⇒

⇒ ⇒

factorizing, we get that:

  ⇒

then, the solutions are: or

nothing extraneous has been found!

answer:   35 % is the probability of a late departure or an early arrival.

step-by-step explanation:

let l represents the late departure and e represents the early departure.

then, according to the question,

p(l) = 12 %,   p(e) = 27 % and = 4 %

and, we have to find out,

but, we know that,

which is the required equation that will use to find the probability of a late departure or an early departure.

therefore,   the probability of a late departure or an early arrival =   35 %