20, 10 line segments each with 2 ends = 20
To solve for x just isolate x by moving the other variables so....:
First add c to both sides
g+c= y+x
Subtract y from both sides
g+c-y= x
That should be your final answer (we cannot come up with an actual digit for x because there are no numbers in this equation we simply can make an equation for x)
Two lines are perpendicular if and only if the product of their slopes is - 1.
So, you just need to find the slope of each line and find out the product of their slopes.
I will do one example for you.
L1: y = 3x + 5
L2: y = - 3x + 14
L3: y = -x/3 + 14
The slope of a line is the coefficient of the x.
So the slopes are:
L1: slope 3
L2: slope -3
L3: slope -1/3
So now multiply the slopes of each pair of lines:
L1 and L2: 3 * (-3) = - 9 => No, they are not perpendicular
L2 and L3: (-3) * (-1/3) = 1 => No, they are not perpendicular
L1 and L3: (3) * (-1/3) = -1 => Yes, they are penpendicular.

Applying the factorization method, for example:




Applying the factorization method:



Multiply 18 pencils by 2 times colored markers and the answer will be 36
18 times 2 = 26