We have this equation for the slope is: y=mx+b which m is the slope and b is the y-intercept, so we have y=20-15x or y=-15x+20, and we already know that the slope is -15 and y-intercept is 20. As a result, the student's error is that he thinks that 20 is the slope because it is the first number. Hope it help!
Answer:
12
Step-by-step explanation
so what I did is I divided 15 by 5 to get 3 also 9 divided by 3 equals 3 to so you could of also done that.
then i multiplied to 4 x 3 to get the missing side length which equals 12
A)
To be similar triangles have to have equal angles
triangle ZDB'
1)angle Z=90 degrees
triangle B'CQ
1) angle C 90 degrees
angle A'B'Q=90
DB'Z+A'B'Q+CB'Q=180, straight angle
DB'Z+90+CB'Q=180
DB'Z+CB'Q=90
triangle ZDB'
DZB'+DB'Z=180-90=90
DB'Z+CB'Q=90
DZB'+DB'Z=90
DB'Z+CB'Q=DZB'+DB'Z
2)CB'Q=DZB' (these angles from two triangles ZDB' and B'CQ )
3)so,angles DB'Z and B'QC are going to be equal because of sum of three angles in triangles =180 degrees and 2 angles already equal.
so this triangles are similar by tree angles
b)
B'C:B'D=3:4
B'D:DZ=3:2
CQ-?
DC=AB=21
DC=B'C+B'D (3+4= 7 parts)
21/7=3
B'C=3*3=9
B'D=3*4=12
B'D:DZ=3:2
12:DZ=3:2
DZ=12*2/3=8
B'D:DZ=CQ:B'C
3:2=CQ:9
CQ=3*9/2=27/2
c)
BC=BQ+QC=B'Q+QC
BQ' can be found by pythagorean theorem
Answer:
a. 
b. His teacher will receive more pencils (See explanation).
Step-by-step explanation:
a. The total number of pencils Louis brings to school is:
Then, in order to calculate the number of pencils Louis’s teacher will receive after he gives each of his 15 classmates an equal number of pencils, you need to solve the division show in the picture attached.
Notice that the remainder obtained is: 
.
<em>This means that Louis’s teacher will receive 4 pencils.</em>
b. If Louis decides instead to take an equal share of the pencils along with his classmates, his teacher will receive more pencils; because the amount of pencils each classmate will receive will be less. This means that the number of pencils leftover will increase, leaving more pencils for his teacher.
