Asap ! i have no clue how to do this !

A)

Equation:  RS + ST = RT

               (2x + 10) + (x-4) = 21

Solve:

2x+10 + x-4 = 21

Combine like terms:

3x + 6 = 21

Subtract 6 from each side:

3x = 15

Divide both sides by 3:

X = 15/3

X = 5

Now replace x with 5 in each equation:

RS = 2x+10 = 2(5) +10 = 10+10 = 20

ST = x-4 = 5-4 = 1

B)

Equation:  RS + ST = RT

               (3x - 16) + (4x-8) = 60

Solve:

3x-16 + 4x-8 = 60

Combine like terms:

7x - 24 = 60

Add 24 to both sides:

7x = 84

Divide both sides by 7:

x = 84/7

X = 12

RS = 3x-16 = 3(12) - 16 = 36-16 = 20

ST = 4x -8 = 4(12) -8 = 48 - 8 = 40

C)

Equation: RS + ST = RT

                 2x-8 + 11 = x+10

Solve:

2x-8 + 11 = x +10

Simplify left side:

2x +3 = x+10

Subtract 3 from both sides:

2x = x +7

Subtract 1x from each side:

x = 7

RS = 2x -8 = 2(7) - 8 = 14-8 = 6

RT = x+10 = 7+10 = 17

"it's not the heat, it's the humidity".   that's a partly valid phrase you may have heard in the summer, but it's actually both.   the heat index, also known as the apparent temperature, is what the temperature feels like to the human body when relative humidity is combined with the air temperature.   this has important considerations for the human body's comfort.   when the body gets too hot, it begins to perspire or sweat to cool itself off.   if the perspiration is not able to evaporate, the body cannot regulate its temperature.   evaporation is a cooling process.   when perspiration is evaporated off the body, it effectively reduces the body's temperature.   when the atmospheric moisture content (i.e. relative humidity) is high, the rate of perspiration from the body decreases.   in other words, the human body feels warmer in humid conditions.   the opposite is true when the relative humidity decreases because the rate of perspiration increases.   the body actually feels cooler in arid conditions.   there is direct relationship between the air temperature and relative humidity and the heat index, meaning as the air temperature and relative humidity increase (decrease), the heat index increases (decreases).

step-by-step explanation:

answer: 4  

the square root of 16 is 4. it is a very simple mathematic concept. a square root when a number multiplied by itself will result in a number. here, the number 16 comes when 4 is multiplied by 4. hence the square root of 16 is 4. you can always figure out a square root by the inverse operation of squaring.