Question

if de = x + 3, ef = 4, and df = 2x, what is de? simplify your answer and write it as a proper fraction, mixed number, or integer.

Explanation:

Step1: Set up equation

Since $DE + EF=DF$, we have $(x + 3)+4 = 2x$.

Step2: Simplify left - hand side

$x+3 + 4=x + 7$, so the equation becomes $x + 7=2x$.

Step3: Solve for x

Subtract $x$ from both sides: $x+7-x=2x - x$, which gives $x = 7$.

Step4: Find DE

Substitute $x = 7$ into the expression for $DE$. Since $DE=x + 3$, then $DE=7 + 3=10$.

Answer:

10