The easiest way to think of these is to put them in terms of percentages. Obviously, if you are SAVING 25%, you are SPENDING 75%. So if she SPENDS 13.50, we can easily use the 75% in an equation. $13.50 = .75x, with x being what the shoes cost originally. The .75 indicates that she is spending 75% of what the original cost is. You don't have any examples to pick from, but this is the best way to explain what one of the equations could be. You could also base it on money saved, but the equation is not quite as neat.
The area is 1680 ft. squared
Answer: h(x) = -1200x^2 + 1950x + 4950
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Work Shown:
f(x) = revenue from the north
f(x) = -750x^2 + 1500x + 2250
g(x) = revenue from the south
g(x) = -450x^2 + 450x + 2700
h(x) = total revenue, ie add the two revenues
h(x) = f(x) + g(x)
h(x) = (-750x^2+1500x+2250)+(-450x^2+450x+2700)
h(x) = -1200x^2 + 1950x + 4950
A₅ = 1/16 and r= 1/4
Let see how to build up this formula that is going to give that term of rank n
1st term =a₁ = To be calculated
1st a₁ = a₁ x r°
2nd a₂ = a₁ x r¹
3rd a₃ = a₁ x r²
4th a₄ = a₁ x r³
5th a₅ = a₁ x r⁴
.......................
.......................
nth : a(n) = a₁ x r⁽ⁿ-¹)
Note when that the subscript of a is the same as the exponent mines 1
We know the ratio r =1/4 & the fifth term, a₅ =1/16 (given). Now let's apply the formula to calculate the unknown a₁.
a(n) = a₁ x r⁽ⁿ-¹) ==>a₅ = a₁ x (1/4)⁽⁵⁺¹⁾ ===> 1/16 = a₁ x (1/4)⁴
1/167 = a₁ (1/256) ==> a₁ =16 & the formula becomes
a₅ = 16(1/4)⁴
