Imagine first splitting 6 wholes up into fourths. That means that, for each whole (each 1) in 6, we're creating 4 equal slices. This gives us 4 x 6 = 24 total slices, which we call <em>fourths</em>. How many groups of <em>3 fourths </em>(3/4) can you make out of those <em>24 fourths </em>(24/4)? If we throw aside the label <em>fourths</em> for a minute, in general, if we have 24 <em>things</em>, how many groups of 3 <em>things</em> can we make out of those? Well, our answer there would just be 24 ÷ 3 = 8 groups.
The same thing applies to fourths. If we have 24/4, and we divide it by 3/4, we get 24 ÷ 3 = 8 groups again, so our answer is <em />8 3/4-pound packages.
click on picture, sorry if it's hard to read, but my phone messed up the typing
W+d=869
w=d-81
plug in
(d-81)+d=869
2d-81=869
+81 both sides
2d=950
÷2 both sides
d=475
dryer cost $475
let's check w=475-81
w=394
475+394=869
869=869
the solution is true :)
Answer:
•cos(s+t) = cos(s)cos(t) - sin(s)sin(t) = (-⅖).(-⅗) - (√21 /5).(⅘) = +6/25 - 4√21 /25 = (6-4√21)/25
•cos(s-t) = cos(s)cos(t) + sin(s)sin(t) = (-⅖).(-⅗) + (√21 /5).(⅘) = +6/25 + 4√21 /25 = (6+4√21)/25
cos(t) = ±√(1 - sin²(t)) → -√(1 - sin²(t)) = -√(1 - (⅘)²) = -⅗
sin(s) = ±√(1 - cos²(s)) → +√(1- cos²(s)) = +√(1 - (-⅖)²) = √21 /5
