SOLUTION: 1. 3x + y = 6 x - y = 1 2. If x Varies directly as y^2, and x= 20 when y= 2, find x when y= 10.

Question 73404This question is from textbook
: 1. 3x + y = 6
x - y = 1
2. If x Varies directly as y^2, and x= 20 when y= 2, find x when y= 10. This question is from textbook

Answer by jim_thompson5910(35256) (Show Source): You can put this solution on YOUR website!


    3x + y = 6
     x - y = 1

Add the 2 equations. Add 3x to x, y to -y, and 6 to 1


    4x     = 7

Now solve for x

Plug this into

Check:


    3(7/4) + 3/4 = 6
      7/4 - 3/4 = 1


    21/4 + 3/4 = 6
      4/4 = 1


    24/4 = 6
      1=1 Works


      6 = 6 Works
      1 = 1 Works

Since x varies directly as y^2, the equation looks like

So just plug in x=20 and y=2 to find k

Now plug k into the equation to find x when y=10

Plug in y=10

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