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horrorfan [7]
3 years ago
7

DE=4x+10, EF=2x-1, and DF=9x-15, find DF

Mathematics
1 answer:
masya89 [10]3 years ago
3 0

DE and EF are segments of the line DF, so they will add up to DF. This can be represented with this equation:

(4x + 10) + (2x - 1) = 9x - 15

Combine like terms:

4x + 2x = 6x

10 + (-1) = 9

6x + 9 = 9x - 15

Add 15 to both sides:

6x + 24 = 9x

Subtract 6x from both sides:

24 = 3x

Divide both sides by 3 to get x by itself:

\boxed{x = 8}

The value of x will be 8.

Plug this value of x into the expression for DF:

9(8) - 15 = 72 - 15 = \boxed{57}

DF will equal 57.

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