Answer:
The correct answer is D. 126
Step-by-step explanation:
In order to solve this exercise, we need to know that two straight triangles that are sharing a vertex like in this picture are considered similar triangles. One property of the similar triangles is that exist a linear relationship between its sides. In this exercise, one triangle is ABC and the other CDE.
The relationship that we can write is between the length of its sides.
The relationship is a division between the length of the sides :
⇒
Solving the equation
⇒
If the side AC is the length is
The correct option is D. 126
Answer:
second option
Step-by-step explanation:
Given
+ 6x² + 5 = 0
let u = x², then
u² + 6u + 5 = 0 ← in standard form
(u + 1)(u + 5) = 0 ← in factored form
Equate each factor to zero and solve for u
u + 1 = 0 ⇒ u = - 1
u + 5 = 0 ⇒ u = - 5
Change u back into terms of x, that is
x² = - 1 ( take the square root of both sides )
x = ± = ± i ( noting that
= i ), and
x² = - 5 ( take the square root of both sides )
x = ± = ±
= ±
×
= ± i
Solutions are x = ± i and x = ± i