Question

The table shows how much Li earns for moving different numbers of lawns. Write an algebraic expression that describes the total earnings for n lawns.

Answer 1

Answer:

15n

Step-by-step explanation:

Given

The above table

Required

The formula of the table

First, calculate the slope (m)

$m = \frac{y_2 - y_1}{n_2 - n_1}$

Where:

n = Number of Lawns

y = Earnings

$(n_1,y_1) = (2,30)$

$(n_2,y_2) = (5,75)$

So, we have:

$m = \frac{75 - 30}{5 - 2}$

$m = \frac{45}{3}$

$m = 15$

The equation is then calculated as:

$y = m(n- n_1) + y_1$

This gives:

$y = 15(n- 2) + 30$

$y = 15n- 30 + 30$

$y = 15n$

Hence:

B is correct