Answer:
z = 0
Step-by-step explanation:
3 (z + 7) = 21
3z + 21 = 21
3z = 0
z = 0
K is the slope of the line formed by connecting the points.
Use slope formula:

where the 2 points are the end points of the line (First and last going Left to right)

Substitute into slope formula

You can check if this is correct by going back to graph and going "up 7" and "over 2" to get from one point to the next.
Using the graph that is included, look at the points given. For example (30, 3). There would be 30 vegetarian dishes and 3 steak dinners for a total of 33 meals. If that is plugged into the cost equation 20(30)+3(30) it would equal $690. The next point (33, 1) would cost 20(33) + 30(1) = $690 and but gives 34 meals. However, 34 vegetarian meals would only cost 20(34)=$680 and have 34 meals.
If both types of meals need to be purchased, 33 vegetarians and 1 steak. If only vegetarians are purchased, the cost is cheaper by $10.
<u>Answer</u> : The demonstration is below :)
Step-by-step explanation :
<u>We use Pythagoras' </u><u>theorem </u><u>:</u>
- In the triangle ABC we have :
AB² = AC² - BC² = 15² - 9² = 144 = 12²
- In the triangle ABD we have :
DB² = AD² - AB² = 13² - 12² = 5²
cos(a) = BD/AD = 5/13