Answer:
27
Step-by-step explanation:
If Fiona's age is x, Dan and Gavyn's ages respectively are x + 8 and x - 9. We can write:
x + x + 8 + x - 9 = 56
3x - 1 = 56
3x = 57
x = 19
The eldest is Dan (because x + 8 > x and x + 8 > x - 9). His age is x + 8 = 19 + 8 = 27.
Max mows a yard in 45 minutes and Jan takes twice as long mowing the same yard. If Max and Jan both work together, it will take approximately 30 minutes to for them both to mow the yard.
It take Max 1 minute to mow 1/45 of the yard.
It takes Jan 1 minute to mow 1/90 of the yard.
1/45+1/90 =3/90 = 1/30 of the yard can be mowed by both in just one minute. This is how to get the answer, 30 minutes.
2cos²x+cos x-1=0
cos x=t
2t²+t-1=0
t=[-1⁺₋√(-1+8)]/2=(-1⁺₋3)/4
We have two possible set solutions:
First set solutions.
t₁=(-1-3)/2=-4/4=-1
cos x=-1 ⇒x=cos⁻¹ (-1)=π +2kπ or 180º+360ºk (k=(...-2,-1,0,1,2...)
Second set solutions:
t₂=(-1+3)/4=2/4=1/2
cos x=1/2 ⇒ x=cos⁻¹ 1/2=π/3+2kπ U 5π/3+ 2kπ or
60º+360ºK U 300º+360ºK (k=...-2,-1,0,1,2,...)
solutions: first set solutions U second set solutions:
Answer in radians : π +2kπ U π/3+2kπ U 5π/3+ 2kπ (k=...-1,0,1,...)
Answer is degrees: 180º+360ºk U 60º+360ºK U 300º+360ºK (k=...-2,-1,0,1,2,...)
I believe it would be 3 but dont take my word
