All the interior angles of a triangle always add up to 180 degrees.
3x + (2x + 20) + (4x - 20) = 180
3x + 2x + 20 + 4x - 20 = 180
3x + 2x + 4x + 20 - 20 = 180
10x = 180
x = 180/10
Therefore, x = 18
Given:
Planes X and Y are perpendicular to each other
Points A, E, F, and G are points only in plane X
Points R and S are points in both planes X and Y
Lines EA and FG are parallel
The lines which could be perpendicular to RS are EA and FG.
<u>Given</u>:
The given monomial expression is 
We need to simplify the given monomial expression.
<u>Simplification:</u>
Let us simplify the given expression.
Dividing the numbers 16 and 4, we get;

Let us apply the exponent rule
in the above expression.
Thus, we get;

Subtracting the numbers in the numerator of the above expression, we get;

Thus, the simplified expression is 
To do this, you have to plug each x value into the rule.
1.y = 15 - 3×2
y = 15 - 6
y = 9
So the first y value would be 9.
2.y = 15 - 3×3
y = 15 - 9
y = 6
3. y = 15 - 3×4
y = 15-12
y = 3
4. y = 15 - 3×5
y = 15-15
y = 0
Hope this helps!