Shelly is going shopping at the mall to buy three pairs of shoes. she has a coupon for $2 off per pair of shoes after buying the first pair for full price. shelly is willing to spend $80 to $122 not including tax. if the shoes she purchases are all the same price, what is the least and most amount she can spend per pair.

Lest amount : $28

Most amount : $42

Step-by-step explanation:

Hi, to answer this question we have to write an inequality using the information given:

So, without the coupon the inequality is:

80 ≤ 3x ≤122

Where x is the price of each pair of shoes.(multiplied by 3 because she wants to buy 3 pairs)

Since she has a  $2 off coupon  per pair after the first, we can say that she has $4 added to her budget ( $2 x 2 pairs ).

So the final inequality is

84 ≤ 3x ≤126

Solving:

84/3 ≤ x ≤126/3

28 ≤ x ≤42

Least amount: $28

Most amount: $42

"standard form:

3x2 + 14x − 10 = 0

solutions based on quadratic formula:

x1   = −14 − √ 142 − 4×3×(−10) /   2×3   = −14 − 2 × √ 79 /   6   ≈ −5.296

x2   = −14 + √ 142 − 4×3×(−10) /   2×3   = −14 + 2 × √ 79 /   6   ≈ 0.629