Question

If C is the midpoint of EF, C has coordinate -8, F has coordinate 4, then find the coordinate of E

Answer 1

Answer:    -20

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Work Shown:

Let x be the location of E on the number line.

Since C is the midpoint of E and F, this means we can find C's location by adding E and F together and dividing that sum by 2

midpoint = (endpoint1 + endpoint2)/2

C = (E+F)/2

Plug in E = x, C = -8 and F = 4. Then solve for x

C = (E+F)/2

-8 = (x+4)/2

(x+4)/2 = -8

x+4 = 2(-8) .... multiplying both sides by 2

x+4 = -16

x = -16-4 .... subtract 4 from both sides

x = -20

The location of point E on the number line is -20

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As a check, lets add E and F to get E+F = -20+4 = -16

Then cut this in half to get -16/2 = -8, which is the proper location of point C

This confirms our answer.