What is the first step in determining if 6 is a solution to 3x=18?

An equation is an expression that involves a variable, and the goal is to find one (or more) value(s) for the variable such that the equation becomes an indentity (i.e. left and right hand sides are the same).

So, in order to check wether 6 is a solution to your equation, you have to replace every occurrence of "x" with "6". In this case, the variable appears only once, so the equation becomes

which is true, so 6 is indeed a solution

Look at the image below:

Step-by-step explanation:

last option

step-by-step explanation:

given that δdef is right and isoceles,

assuming that side df is the hypotenuse means that de an ef are the other 2 sides that intersect at 90° and are of equal length.

because they are of equal length, we can say that they are congruent

because they intersect at 90°, their slopes must be opposite reciprocals.

only the last option satisfies these conditions.

d. bc = 12 and ef = 16

step-by-step explanation:

we are given that δabc : δdef such that .

also, it is given that

so, from the options, we need that .

a.

b.

c.  

d.

as, we can see that only option d gives the same ratio as i.e. .

hence, the possible lengths are bc = 12 and ef = 16.