Answer:
Step-by-step explanation:
Newton's Law of Cooling
Tf=Ts+(Ti-Ts)e^(-kt) where Tf is temp at time t, Ts is temp of surroundings, Ti is temp of object/fluid. So we need to find k first.
200=68+(210-68)e^(-10k)
132=142e^(-10k)
132/142=e^(-10k)
ln(132/142)=-10k
k=-ln(132/142)/10
k≈0.0073 so
T(t)=68+142e^(-0.0073t) so how long until it reaches 180°?
180=68+142e^(-0.0073t)
112=142e^(-0.0073t)
112/142=e^(-0.0073t)
ln(112/142)=-0.0073t
t= -ln(112/142)/(0.0073)
t≈32.51 minutes
1. You con solve the quadratic equation x^2+20x+100=50<span> by following the proccedure below:
2. Pass the number 50 from the right member to the left member. Then you obtain:
x^2+20x+100-50=0
</span><span> x^2+20x+50=0
</span><span>
3. Then, you must apply the quadratic equation, which is:
x=(-b±√(b^2-4ac))/2a
</span><span>x^2+20x+50=0
</span><span>
a=1
b=20
c=50
4. Therefore, when you substitute the values into the quadratic equation and simplify ir, you obtain that the result is:
-10</span>±5√2 (It is the last option).
