Question

which of the following statements is incorrect? (8x - 24) 40 (6x + 10) o x = 8 o df = 40 o de = 58 o fe = 58

Explanation:

Step1: Assume the triangle is isosceles

If the triangle $\triangle DEF$ is isosceles, assume $DF = DE$. Then $8x - 24=40$.
Solve the equation $8x - 24 = 40$:
Add 24 to both sides: $8x=40 + 24$, so $8x=64$.
Divide both sides by 8: $x = 8$.

Step2: Calculate side - lengths

When $x = 8$:
$DF=8x - 24=8\times8 - 24=64 - 24 = 40$.
$FE=6x + 10=6\times8+10=48 + 10=58$.
$DE = 40$.

Answer:

C. $DE = 58$