**Answer:**

C. Determine the principal square root of both sides of the equation.

**Step-by-step explanation:**

**Answer:**

r= -15

**Step-by-step explanation:**

when a negative subtracts a negative you just add more negatives

2r

r= -15

2x-15= -30, -30- -6= -36

Do recall that squaring and the *radical sign* cancel each other out... like so:(

)

= a

When you put it that way, it isn't enough :P

(

)

= a

(

)

=?

so you start with

(

)

=

8x+1=25 <-- subtract 1 to both sides

8x=24 <- divide 8 to both sides

x= 3

To find out if it's an extraneous solution ask yourself: It mustn't result in a radical that I like to call... 'illegal'. Plug it into the radicand 8x+1 and make sure you get something that is not a negative number.... so, DO you get a negative number when you plug in x = 3 into the radicand?

(extraneous solution is a invalid solution)

**x=3 not extraneous**
**Answer:**

5π/2 cm

**Step-by-step explanation:**

Given,

Radius ( r ) = 10 cm

Since, the angle is 90, the length of the the arc is π r/ 4

π * 10 / 4

= 10π/4

= 5π/2

Because it's before anything else in any equations <span />