Get into form a(x-h)²+k
complete the square
-3x²-18x-31
group x terms
(-3x²-18x)-31
undistribute the -3
-3(x²+6x)-31
take 1/2 of the linear coefient (6) and squaer it
6/2=3, 3²=9
add positive and negative of it inside parenthasees
-3(x²+6x+9-9)-31
complete the square
-3((x+3)²-9)-31
expand
-3(x+3)²+27-31
-3(x+3)²-4 is vertex form
Answer:
Thanks for the points :)>
Step-by-step explanation: yeahhh shawtyyy
Answer:
Step-by-step explanation:
The second one.
Let's factorise it :

![\: {\qquad \dashrightarrow \sf {x}^{3} (x + 3) + [-5(x + 3)] }](https://tex.z-dn.net/?f=%5C%3A%20%7B%5Cqquad%20%20%5Cdashrightarrow%20%5Csf%20%20%20%20%7Bx%7D%5E%7B3%7D%20%28x%20%2B%203%29%20%2B%20%5B-5%28x%20%2B%203%29%5D%20%20%7D)
Using Distributive property we get :



⠀
Therefore,

Answer:
8
Step-by-step explanation:
378-36-270=9x
72=9x
72÷9=9x÷9
8=x
X=8