Respuesta :

Answer:

x = -9

Step-by-step explanation:

Given:

BC = x + 19

ST = x + 29

Required:

Value of x

Solution:

Midsegment theorem states that the midsegment of a triangle = ½ of the length of its third side

Thus:

BC = ½(ST)

Substitute

x + 19 = ½(x + 29)

Multiply both sides by 2

2(x + 19) = x + 29

2x + 38 = x + 29

Collect like terms

2x - x = -38 + 29

x = -9