Answer:
9a + 6b and 5c - 3d
Step-by-step explanation:
(a)
4a + 7b + 5a - b ← collect like terms
= (4a + 5a) + (7b - b)
= 9a + 6b
(b)
6c + 4d - c - 7d ← collect like terms
= (6c - c) + (4d - 7d)
= 5c - 3d
Given:
Joining fee = $28
Fee of each event = $4
To find:
Total cost for someone to attend 4 events.
Solution:
Let the number of events be x and total fee be y.
Fee for 1 event = $4
Fee for x events = $4x
Joining fee remains constant. So, the total fee is

Substitute x=4 in this equation.



Therefore, total cost of 4 events is $44.
Answer:
282.74
Step-by-step explanation:
Solving a system of linear equations, we conclude that the measure of side Z is 2√13
<h3>How to find the measure of side Z?</h3>
Remember the Pythagorean theorem. It says that the square of the hypotenuse is equal to the sum of the squares of the legs.
In the image, we can identify 3 right triangles, and with the Pythagorean theorem, we can write a system of 3 equations.
x^2 = y^2 + 4^2
z^2 = y^2 + 9^2
(4 + 9)^2 = z^2 + x^2
We want to solve that for z.
Now, the second equation can be rewritten to:
y^2 = z^2 - 9^2
Now let's replace the first equation into the third one, so we get:
(4 + 9)^2 = z^2 + (y^2 + 4^2)
Now we can replace y^2 by z^2 - 9^2
(4 + 9)^2 = z^2 + ((z^2 - 9^2) + 4^2)
Now we can solve this:
(13)^2 = z^2 + z^2 - 9^2 + 4^2
(13)^2 + 9^2 - 4^2 = 2*z^2
104/2 = z^2
52 = z^2
√52 = z
√(4*13) = z
√4*√13 = z
2√13 = z
We conclude that the measure of side Z is 2√13
If you want to learn more about systems of equations:
brainly.com/question/13729904
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Ok, to show that she is incorrect we can use any other number in both equations and they will not be equal. the number she used does turn out equal but that does not mean the equations are equal.
for example
2 times 3=6
3 to the power of 2 is 9
that shows the expressions are not equal