Answer:
66
Step-by-step explanation:
If there are <em>n</em> students, then the number of pairs is
.
With 12 students,
pairs can be formed.
The reason the formula works is this: Each of the 12 students can be paired with 11 other students (no student is paired with him/her self). But counting 12 x 11 = 132 counts each pair <u>twice</u>. Example: student A can be paired with student B,..., student B can be paired with student A. The pair was counted two times.
See the attached image that shows pairings of 5 students. There are
5(5 - 1)/2 = 5(4)/2 = 10 pairs.
Answer: y=Mx+b
Step-by-step explanation:
G
Answer:
C=14pi cm
A=49pi cm^2
Step-by-step explanation:
1) Circumference of a circle is 2piR and R=7cm
C=2pi(7)
C=14pi cm
2) Area of a circle is piR^2 and R=7cm
A=pi (7)^2
A=49pi cm^2
Answer:
C) -1
Step-by-step explanation:
(ax+3)²=36
<em>Square root both sides</em>
ax+3=6
<em>Subtract 3 from both sides</em>
ax=3
<em>Put x in</em>
-3a=3
a= -1
C) -1 would work.