Answer:
Exact form : - 1/5
Decimal form : -0.2
Step-by-step explanation: Substitute the value of the variable into the equation and then simplify. 
Hope this helps you out. If not, comment and let me know. Good luck, mate! ☺
-Leif the Insane Puppy Loving Weirdo-
 
        
             
        
        
        
(5x²+4x-80)(x²-5x-24)=5x²(x²-5x-24)+4x(x²-5x-24)-80(x²-5x-24)
{distributive property of multiplication}
                                  =5x^4-25x³-120x²+4x³-20x²-96x-80x²+400x+1920
                                  =5x^4-21x³-220x²+304x+1920
This is the answer.
        
             
        
        
        
Answer:
fnkjsbngkjdbntlgnds bfdln
Step-by-step explanation:
 
        
                    
             
        
        
        
Answer:
x = 25
Step-by-step explanation:
Both angles are supplementary and will add up to 180°
5x - 5 + 2x + 10 = 180
collect like terms
5x + 2x +10 -5 = 180
7x + 5 = 180
7x = 180 - 5
7x = 175
x = 175/7
x=25