We have

And we want

Another way to read it is

It should be clear that the solution is 
Step-by-step explanation:
our equation is x²+16x = -44
- x²+16x= -44
- x² is the first term so weill have in the middle 2*x* a number
- x²+2*x*8 = -44
- the third term is 8² wich is 64 so we will add it in both sides
- x²+2*x*8+64 = -44+64
- (x+8)² = 20
Now that we have completed the perfect square let's solve the equation
- (x+8)² = 20
- x+8 =
or x+8= -
- x = -8+
or x = -8- 
so the first answer is the correct one
64; 8 +/- 
The answer is 2/6 in the fourth decimal place
To do this without a calculator, it may be easier to break the number into smaller parts.
420 * 6
= (400 * 6) + (20 * 6)
= 2400 + 120
= 2520
Hope this helps! :)
Equation: 17 + x = 23
To solve this you would do 23 - 17 to get x
x = 6