This is (x - 6)*x^1/2(x + 3)
= x^1/2 (x^2 - 3x - 18)
= x^(5/2) - 3x^(3/2) - 18x^(1/2)
In order for the triangle to be isosceles, we have to set two lengths of the triangle equal to each other.
Let's take the lengths 5x-12 and x+20 and set them equal to each other.
5x - 12 = x + 20
Combine like terms by moving them over to their respective sides.
Subtract x from both sides of the equation.
4x - 12 = 20
Add 12 to both sides of the equation.
4x = 32
Divide both sides by 4.
x = 8
Check your answer by substituting.
5x - 12 = x + 20
5(8) - 12 = 8 + 20
40 - 12 = 28
28 = 28
Solution: x = 8
This will be easier to write, and a lot easier to read, if we temporarily
use another symbol ... say, 'Q' ... to represent ' sin(2x) ' .
Here we go:
Original equation: Q² - 0.5 Q = 0
Factor the left side: Q (Q - 0.5) = 0
This equation is true if either factor is zero:
-- If Q=0, then sin(2x) = 0
2x = 0°, 180°, 360°
x = 0°, 90°, 180°
-- If (Q-0.5) = 0, then Q = 0.5
sin(2x) = 0.5
2x = 30°, 150°
x = 15°, 75°
The whole collection of solutions
between 0° and 360° :
x = 0°, 15°, 75°, 90°, 180° .
