Acertain triathlon consists of a 2.2 mile swim, a 108 mile bicycle ride, and a 25.4 mile run. at one point, a participant had completed twice as many miles as the number of miles left to complete. how many miles had he completed at that mark?

He had completed at that mark  90.4 miles

Step-by-step explanation:

step 1

Find the total miles of the triathlon

we have

swim ----> 2.2 mi

bicycle ---> 108 mi  

run ----> 25.4 mi

Adds the number of miles

step 2

Find out how many miles he had completed at that mark

Let

x ---->  the number of miles left to complete

we know that

At one point a participant had completed 135.6-x

At one point, a participant had completed twice as many miles as the number of miles left to complete

so

solve for x

He had completed at that mark

the polynomial is a perfect square trinomial of the form a^2-2ab+b^2:

option a. true

step-by-step explanation:

9x^2-12x+4

comparing with the form a^2-2ab+b^2

1.) a^2=9x^2

solving for a: square root both sides of the equation:

sqrt(a^2)=sqrt(9x^2)

a=sqrt(9) sqrt(x^2)

a=3x

2.) b^2=4

solving for b: square root both sides of the equation:

sqrt(b^2)=sqrt(4)

b=2

to be a perfet square trinomial 2ab must be equal to 12x. let's check:

2ab = 2 (3x) (2)

2ab = 12x

correct

b. f(x) = –√x + 3this is the correct answer