How do you solve x^2+11x+18=0 with either quadratic formula. factoring. or squarerooting

I always prefer factoring, if there are simple factors.
There are simple factors here.

x² + 11x + 18 = 0

(x + 2) (x + 9) = 0

The left side is zero if either factor is zero.

First factor:
x + 2 = 0
x = -2

Second factor:
x + 9 = 0
x = -9

 

AAS Theorem

Step-by-step explanation:

In the given figure , we have

By CPCTC [Congruent parts of congruent triangles are congruent], we have

                 (1)

             (2)

Now in , we have

                     (From 1)

                  (From 2)

                    (Vertical angles)  

Therefore by AAS theorem of congruence , we have

   

AAS theorem of congruence says that if two angles and a non-included side of a triangle are congruent to the corresponding parts of other triangle then the triangles are said to be congruent.