You will get a brain list if the answer is right.

15

Step-by-step explanation:

We know according to the figure that 9^2+12^2 = z^2,

as a result, we know that z^2 = 225

and z = 15

Another method is to recognize that this figure is similar to a 3-4-5 triangle. According to the converse of the Hypotenuse-Leg theorem, we get that the third length of the triangle is 15

x= -3 and

step-by-step explanation:

to find the roots of a cubic, use division or factoring to find the factors then set equal to 0. as this is a difference of cubes, it factors into

where a is the cube root of .

here   this is 27 and the cube root of 27 is 3. so we write using the form:

.

set each factor to 0 and solve for x.

x-3=0

x=3

the quadratic expression does not factor and must be solved using the quadratic formula.

where a = 1, b=3, and c=9

this cubic has two complex roots.