To solve this we need to form 2 equations with only 2 variables.
x+4y-5z=-7
2x+y+5z=8
3x+5y=1
15x+10y+15z=35
6x+3y+15z=24
9x+7y=11
Now we need to use these to find x and y
9x+15y=3
9x+7y=11
8y=-8
y=-1
Therefore:
x=2
From this we can find that:
2(2)-1+5z=8
Therefore z=1
The answer is x=2, y=-1, z=1
The value of x is 5 by using external angle
40, because you have to divide 2.10 by 0.42 and when you do so you get 5, then you multiply by 8 because 8 pencils cost 0.42.
See the explanation
<h2>
Explanation:</h2>
Since you don't provide any graph I can't give you an exact answer. However, I'll give you the fourth graph for this problem. So we have:
<h3>First:</h3>
We have the inequality:

The symbol < tells us that the line is dotted and the shaded region is below the line. Also, the slope is 3 and the y-intercept is 2. So as x increases one unit y increases 3, so if (0, 2) which is both a point and the y-intercept of the line, then (1, 5) will also be a point on the line. By using graphing tool we get the first graph below.
<h3>Second:</h3>
We have the inequality:

This case is similar to the previous one. The only difference is that the shaded region is above the line. The graph is the second one below.
<h3>Third:</h3>
We have the inequality:

Again the line is shaded under the graph. Also, the slope is 1/3 and the y-intercept is 2. So as x increases one unit y increases 1/3, or in other words, as x increase 3 units y increases one unit, so if (0, 2) which is both a point and the y-intercept of the line, then (3, 3) will also be a point on the line. By using graphing tool we get the third graph below.
<h3>Fourth:</h3>
We have the inequality:

This case is similar to the previous one. The only difference is that the shaded region is above the line. The graph is the fourth one below.
<h2>Learn more:</h2>
Inequalities: brainly.com/question/12890742
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