SOLUTION: I have a homework question that states: Find the possible values of x if the points (x,5) & (-7,-6) are a distance d=146 sqrt apart. The possible values listed for x are: (-13, -

Algebra ->  Graphs -> SOLUTION: I have a homework question that states: Find the possible values of x if the points (x,5) & (-7,-6) are a distance d=146 sqrt apart. The possible values listed for x are: (-13, -      Log On


   

Question 83952: I have a homework question that states: Find the possible values of x if the points (x,5) & (-7,-6) are a distance d=146 sqrt apart. The possible values listed for x are: (-13, -4), (-12, -2), (-12, 2) and (-13, 4). I have tried working out all numbers using the formula (x2-x1)^2+(y2-y1)^2 sqrt and nothing is coming out to 146 sqrt. What am I doing wrong?
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
Start with the given formula
d=sqrt%28%28x%5B2%5D-x%5B1%5D%29%5E2%2B%28y%5B2%5D-y%5B1%5D%29%5E2%29

Now plug in the given points (x,5) and (-7,-6) and the distance d=sqrt%28146%29

sqrt%28146%29=sqrt%28%28x-%28-7%29%29%5E2%2B%285-%28-6%29%29%5E2%29 Plug in the given info

sqrt%28146%29=sqrt%28%28x%2B7%29%5E2%2B%285%2B6%29%5E2%29 Subtract the negatives

sqrt%28146%29=sqrt%28%28x%2B7%29%5E2%2B%2811%29%5E2%29 Add

sqrt%28146%29=sqrt%28%28x%2B7%29%5E2%2B121%29 Square 11

%28sqrt%28146%29%29%5E2=%28x%2B7%29%5E2%2B121 Square both sides

146=%28x%2B7%29%5E2%2B121

146-121=%28x%2B7%29%5E2 Subtract 121 from both sides

25=%28x%2B7%29%5E2 Combine like terms

sqrt%2825%29=x%2B7 Take the square root of both sides

5=x%2B7

5-7=x Subtract 7 from both sides

x=-2 Combine like terms

So the value of x is -2

I'm not sure why the answers are listed in pairs, but I do see a -2 as one of the possible answers.