Answer:
x=4 x=-1
Step-by-step explanation:
x^2-3x-4=0
x^2-4x+x-4=0
x(x-4) + 1(x-4)=0
x+1=0
x=-1
x-4=0
x=4
Answer:
-4<-12
Step-by-step explanation:
True.
Since

,

and the solutions are decreasing functions.
Answer:
8.66214 x 10^11
Step-by-step explanation:
question may ask to round, so the answer may be simplified to 9 x 10^11
Answer:
4
Step-by-step explanation:
1. if the mass of coffee worth $10 is 'x', then its worth is 10x, and the worth of the mixture is 5(x+20);
2. using the previous item it is possible to write the next equation:
5(x+20)=4*20+10*x; ⇒ x=4.
3. the required mass is 4 pounds.