Answer:
The sum of the internal ángles = 360°
(3y+40)° and (3x-70°) are suplementary angles = 180°
then:
(3x-70) + (3y+40) + 120 + x = 360 ⇒ first eq.
(3y+40) + (3x-70) = 180 ⇒ second eq
development:
from the first eq.
3x + x + 3y = 360 + 70 - 40 - 120
4x + 3y = 430 - 160
4x + 3y = 270 ⇒ third eq.
3y = 270 - 4x
y = (270 - 4x) / 3 ⇒ fourth eq.
from the secon eq.:
3y + 3x = 180 + 70 - 40
3y + 3x = 250 - 40
3y + 3x = 210 ⇒ fifth eq.
multiply by -1 the fifth eq and sum with the third eq.
-3y - 3x = -210 ⇒ (fifth eq. *-1)
3y + 4x = 270
⇒ 0 + x = 60
x = 60°
from the fourth eq.
y = (270-4x)/3
y = (270-(4*60)) / 3
y = (270 - 240) / 3
y = 30/3
y = 10°
Probe:
from the first eq.
(3x-70) + (3y+40) + 120 + x = 360
3*60 - 70 + 3*10 + 40 + 120 + 60 = 360
180 - 70 + 30 + 40 + 120 + 60 = 360
180 + 30 + 40 + 120 + 60 - 70 = 360
430 - 70 = 360
Answer:
y = 10
Answer:
see attached
Step-by-step explanation:
I find it convenient to let a graphing calculator draw the graph (attached).
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If you're drawing the graph by hand, there are a couple of strategies that can be useful.
The first equation is almost in slope-intercept form. Dividing it by 2 will put it in that form:
y = 2x -4
This tells you that the y-intercept, (0, -4) is a point on the graph, as is the point that is up 2 and right 1 from there: (1, -2). A line through those points completes the graph.
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The second equation is in standard form, so the x- and y-intercepts are easily found. One way to do that is to divide by the constant on the right to get ...
x/2 +y/3 = 1
The denominators of the x-term and the y-term are the x-intercept and the y-intercept, respectively. If that is too mind-bending, you can simply set x=0 to find the y-intercept:
0 +2y = 6
y = 6/2 = 3
and set y=0 to find the x-intercept
3x +0 = 6
x = 6/3 = 2
Plot the intercepts and draw the line through them for the graph of this equation.
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Here, we have suggested graphing strategies that don't involve a lot of manipulation of the equations. The idea is to get there as quickly as possible with a minimum of mistakes.
<span>Collinear points</span> are points that are on the same line
<h3>
Answer: 130</h3>
Explanation:
Let x be the unknown angle we want to find.
Let y be adjacent and supplementary to x. This means x+y = 180
Let z also be adjacent and supplementary to x. So x+z = 180 also
Subtracting the two equations leads to y-z = 0 and y = z. So effectively we've proven the vertical angle theorem.
Since the supplementary angles to x add to 100, we know that y+z = 100. Plug in y = z and solve for z
y+z = 100
z+z = 100
2z = 100
z = 100/2
z = 50
Therefore,
x+z = 180
x+50 = 180
x = 180-50
x = 130
Lawrence's is the correct answer. he put 3 plates on each box in both situations
