Question

combine like terms (basic, decimals)
score: 3/5 penalty: 1 off
question
the width of a rectangle measures (6.4d + 7.2f) centimeters, and its length measures (9.1d + 9.3f) centimeters. which expression represents the perimeter, in centimeters, of the rectangle?

Explanation:

Step1: Recall perimeter formula

The perimeter $P$ of a rectangle is $P = 2(l + w)$, where $l$ is the length and $w$ is the width.

Step2: Substitute length and width

Substitute $l=(9.1d + 9.3f)$ and $w=(6.4d + 7.2f)$ into the formula: $P=2((9.1d + 9.3f)+(6.4d + 7.2f))$.

Step3: Combine like - terms inside parentheses

$(9.1d+6.4d)+(9.3f + 7.2f)=15.5d+16.5f$. So $P = 2(15.5d+16.5f)$.

Step4: Distribute the 2

$P=2\times15.5d+2\times16.5f = 31d + 33f$.

Answer:

$31d + 33f$