Solve with substitution, show your work. 3x+2y+z=7 5x+5y+4z=3 3x+2y+3z=1

3x + 2y + z = 7   ⇒   z = 7 - 3x - 2y

  5x + 5y + 4z = 3  

= 5x + 5y + 4(7 - 3x - 2y) = 3

= 5x + 5y + 28 - 12x - 8y = 3

= -7x -3y + 28 = 3

= -7x - 3y = -25

  3x + 2y + 3z = 1

= 3x + 2y + 3(7 - 3x - 2y) = 1

= 3x + 2y + 21 - 9x - 6y = 1

= -6x - 4y + 21 = 1

= -6x - 4y = -20

-7x - 3y = -25   ⇒  4(-7x - 3y = -25)   ⇒   -28x - 12y = -100

-6x - 4y = -20   ⇒ -3(-6x - 4y = -20)   ⇒    18x + 12y =  60

                                                                  -10x         =   -40

                                                                       x         =     4

-7x - 3y = -25

-7(4) - 3y = -25

-28  - 3y = -25

        -3y  = 3

           y  = -1

z = 7 - 3x - 2y

  = 7 - 3(4) - 2(-1)

  = 7 - 12 + 2

  = -3

x = 4, y = -1, z = -3

the option best identifies the textual evidence that supports this conclusion is c.) when an argument is over, how many weighty reasons does a man recollect which his heat and violence made him utterly forget? in order to recognize textual evidence is to identify the topic sentence where the author states the main idea. textual evidence is what supports the topic sentence or main idea of a passage.

8.75

how-to:

first, we need to find what we have to work with.

since i know that we have 7 (years) and 0.8 (inches), we can use these to solve and find the equation!

secondly, what you want to do, is see that we need to know how much growth out of the 0.8 inches he got in only 1 year, instead of 7 years.

let's try to divide.

7 ÷ 0.8 = 8.75