The answer is 23.
Good luck :)
        
             
        
        
        
Answer:
x= ±  +2
 +2
Step-by-step explanation:
Use the formula ( b/2) ^2 in order to create a new term. Solve for x by using this term to complete the square.
x= ±  +2
 +2
 
        
             
        
        
        
We know that 
the equation of the vertical parabola in the vertex form is
<span>y=a(x-h)²+k
</span>where 
(h,k) is the vertex of the parabola
if a> 0 then
 the parabola opens upwards
if a< 0 
then the parabola open downwards
in this problem  we have
f(x)=−5(x+7)²<span>+6
</span>a=-5
so
a< 0 -------> the parabola open downwards
the vertex is the point (-7,6) is a maximum
the answer is the option<span>
a = -5, opens down</span>
 
see the attached figure
 
        
        
        
The probability that both marbles will be a red color is:
  
    6.....    ⇔ number that satisfies the constraint
_____
   15.....    ⇔ number of outcomes
        
             
        
        
        
Answer:
Step-by-step explanation:
1) Eliminate parentheses:
   0.1x +18.8 = -4 +2x
   22.8 = 1.9x . . . . . . . . . add 4 - 0.1x
   12 = x . . . . . . . . . . . . . divide by 1.9
__
2) Eliminate parentheses:
   -16 +4x = 0.8x +12.8
   3.2x = 28.8 . . . . . . . . add 16 - 0.8x
   x = 9 . . . . . . . . . . . . . .divide by 3.2
_____
<em>Comments on the solutions</em>
The expression we add in each case eliminates the constant on one side of the equation and the variable term on the other side. That leaves an equation of the form ...
   variable term = constant
We choose to eliminate the smaller variable term (the one with the coefficient farthest to the left on the number line). Then the constant we eliminate is the on on the other side of the equation. This choice ensures that the remaining variable term has a positive coefficient, tending to reduce errors.
__
You can work these problems by methods that eliminate fractions. Here, the fractions are decimal values, so are not that difficult to deal with. In any event, it is good to be able to work with numbers in any form: fractions, decimals, integers. It can save some steps.