Step-by-step explanation:
a=2
b=-7
c=-15
-(-7)+-sq root (-7)²-4(2)(-15) / 2(2)
7 +- sq root 169 / 4
7+- 13 / 4
7+13 / 4, 7-13 / 4
x=5 x=-3/2
 
        
             
        
        
        
Answer:
5.5 days 
Step-by-step explanation:
you need to find the average between them so add them up and divide by 2.
 
        
             
        
        
        
Answer:
y = 6
Step-by-step explanation:
6 * y * 4 = 2 * 72
y = 2 * 72/24 = 6
 
        
                    
             
        
        
        
Answer: -1 and 5.
Step-by-step explanation:
x - 4x = 5 : Move the constant to the left.
x^2 - 4x - 5 = 0 : Rewrite the expression.
x^2 + x - 5x - 5 = 0 : Factor the expressions.
x(x+1) - 5(x+1) = 0 : Factor the expression.
(x+1)(x-5) = 0 : Seperate into possible cases.
x + 1 = 0, x - 5 = 0 : Solve the equations.
x = -1, x = 5 : The equation has 2 solutions.