Answer:

Step-by-step explanation:
<u><em>The picture of the question in the attached figure</em></u>
we know that
The perimeter of a triangle is the sum of the length of their three sides
so

where
a,b,c are the length sides of the triangle
In this problem we have

substitute and solve for the missing length

Semester 1:
let the number of students in the art class be 2a, and the number of the students in the gym class be 7a. (check: the ratio is 2a:7a = 2:7)
so the total number of students is 9a.
semester 2:
the 9a students are go to the art class and gym class at a a ratio of 5: 4,
so 5a students go to the art class, and 4a students go to the gym class.
<span>75 students are in art class in second semester means that 5a=75,
so a=75/5=15.
In the 1st semester the number of students was:
art class: 2a=2*15=30
gym class: 7a=7*15=105</span>
Answer:
yes
Step-by-step explanation:
functions have one input for every output.
the input side has unique and individual numbers therefore it's a function.