Kim and daniel are selling wrapping paper for a school fundraiser. customers can buy rolls of plain wrapping paper and rolls of shiny wrapper paper. kim sold 7 rolls of plain wrapping paper and 8 rolls of shiny wrapping paper for a total of $140. daniel sold 14 rolls of plain wrapping paper and 7 rolls of shiny wrapping paper for a total of $154. find the cost each of one roll of plain wrapping paper and one roll of shiny wrapping paper.

There are two equation:

1) From Kim

2) From Daniel

Let:

x be the cost of rolls of plain wrapping paper

y be the cost of rolls of shiny wrapping paper

Kim:

7x + 8y = 140

Daniel:

14x + 7y = 154

Using elimination method:

(7x + 8y = 140) * -2  (Multiplying the equation by -2)

-14x - 16y = -280

-14x  -16y = -280

14x + 7y = 154

0x - 9y = -126

9y = 126 (Negative sign cancels from both sides)

y = 126 /9

y = 14

The cost of each shiny wrapping paper is $14.

Now solve x, you pick any two equation to solve for x.

7x + 8y = 140

7x + 8(14) = 140 (You know from above y =14)

7x + 112 = 140

7x = 28

x = 28/7

x = 4

The cost of each plain wrapping paper is $4.

Solution: (4,14)

step-by-step explanation:

we are given a graph for system of inequalities.

in order to write the system of inequalities for the given graph, we need to find the inequality for each of the line separately.

let us find the slope of dotted line first.

taking two coordinates on the graph.

let us say (0,0) and (3,1).

let us find the slope of the line now.

slope of the dotted line would be =.

y-intercept of dotted line is y=0 only.

plugging slope m= and b=0 in slope-intercept form y=mx+b, we get

.

the line is shaded up of that dotted line.

therefore, for shading up we would take greater than inequality symbol > .

and because it's a dotted line we would take only > symbol in place of = sign in above equation of line.

therefore, inequality for dotted line would be

let us take two points (3,1) and (0,4) on the solid line.

slope of the solid line would be =.

for the solid line we have y-intercept b= 4.

plugging slope m= -1 and b=4 in slope-intercept form y=mx+b, we get

y = -1x + 4.

the line is shaded down of that solid line.

therefore, for shading down we would take less than inequality symbol < .

and because it's a solid line we would take ≤ symbol in place of = sign in above equation of line.

therefore, inequality for solid line would be