Chapter 12, Problem 85CUR

To determine

To graph the equation $4x+5y=18$ and to check whether the equation is a function.

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Answer to Problem 85CUR

The equation $4x+5y=18$ is a function.

Explanation of Solution

Given information: $4x+5y=18$

Graph:

Interpretation:

S.NO.	$x$	$y=\frac{18-4x}{5}$	$y$
1	-1	$y=\frac{18-4(-1)}{5}$	4.4
2	0	$y=\frac{18-4(0)}{5}$	3.6
3	1	$y=\frac{18-4(1)}{5}$	2.8
4	2	$y=\frac{18-4(2)}{5}$	2

It is relatively easy to determine whether an equation is a function by solving for y. When you are given an equation and a specific value for x, there should only be one corresponding y-value for that x-value. 

Hence, $4x+5y=18$ is a function as there will be different value of y for each value of x.