Answer:
20) 9x - 3
21) 9x + 60
22) 4x - 10
Tip: when it says "___ more/less than," at the beginning you add it at the end.
Explanation:
23) 190 = .10x + 15. x = the amount of copies you get for $190.
subtract 15 from both sides.
175 = .10x
divide by .10 on both sides.
1750 = x. You can get 1750 copies for $190.
24) 150w + .10m = 190. m = miles (w = week)
150 + .10m = 190
subtract 150 from both sides
.10m = 40
divide .10 on both sides.
m = 400. You can drive 400 miles in one week for $190.
25) Here we have to work backwards. Start off with a 1 variable equation. Since L = 2w + 2, let's replace that for the length.
P = 2w + 4w + 4. (4w + 4 because perimeter is 2l + 2w, you have to double the length as well)
Add the w's together and input known values.
124 = 6w + 4
Subtract 4 on both sides
120 = 6w
Divide 6 on both sides
20 = w.
Now we will find the length since we know the width using the equation:
124 = 2(20) + 2L
124 = 40 + 2L
Subtract 40 on both sides
84 = 2L
Divide 2 on both sides
42 = L.
26) Do the same thing as 25.
162 = 2w + 2(w + 63)
162 = 2w + 2w + 126
162 = 4w + 126
Subtract 126 on both sides
36 = 4w
Divide 4 on both sides
9 = w.
9 + 63 = L
72 = L
Hope this helps.