Test the choices !
Pick an even number, and see what each choice does to it.
Let's start with, say, 6 .
We'll try each choice, and see which one produces an odd number:
a). 6 to the 2nd power. . . . . . 6 x 6 = 36. That's not an odd number.
b). 6 + 3 = 9 This could be it. 9 is odd. We'll save this one.
c). 3·6 = 18. That's not an odd number.
d). 6/3 = 2. That's not an odd number.
The only one that gave us an odd number is (b).
Here, angle (3x-1) is supplementary with 5x, so their sum would be equal to 180
3x - 1 + 5x = 180
8x = 180 + 1
x = 181/8
x = 22.625
Hope this helps!
Check the picture below.
bearing in mind that twin sides stemming from a common vertex, will make twin angles at the base, thus 74° has a twin.
It will be A² + B² = C²
So 3²+5² is 34
And the square root of 34 is about 5.83
3² + 5² ≈ 5.83²
Hope that helps :)
