Answer:
Cost of one pencil: 
Cost of one eraser: 
Step-by-step explanation:
Let be "p" the cost in dollars of one pencil and "e" the cost in dollars of one eraser.
Based on the information given in the exercise, you can set up the following system of equations:

You can use the Elimination Method to solve the system of equations.
Multiply the first equation by -3 ad the second one by 4. Then add the equations and solve for "e":
{
Substitute the value of "e" into any original equation and solve for "p":

Please show the question you’re confused about. We can’t help if we don’t know the problem :)
46.8 is 39% of 120. Hope this helped you!
Answer:
I drew more points as uploaded picture.
We have, arc BD + 210 + 90 = 360 deg
(sum of all arcs on circle)
=> arc BD = 360 - 210 - 90 = 60 deg
Here we have angle CBD = (1/2) x arc CD = (1/2) x 90 = 45 deg
(property of angle on circle)
=> angle ABD = angle ABC - angle CBD = 180 - CBD = 180 - 45 = 135 deg
( A, B, C lie on same line => ABC = 180 deg)
Otherwise, we have:
angle BDA = (1/2) x arc BD = (1/2) x 60 = 30 deg
We have: x + angle BDA + angle ABD = 180 deg
(sum of all angles in a triangle)
=> x = 180 - angle BDA - angle ABD
=> x = 180 -135 - 30
=> x = 15 deg
Hope this helps!
:)