Answer:
A
Step-by-step explanation:
I'm pretty sure some smart guy in Greece noticed this but:
Since 4 + 8 = 12, thats the only option where 2 of the smaller sides add up to the big one. I don't know much of the reasoning behind this but my math teacher showed it to us by using Popsicle sticks to make triangles. You can try it if that helps you think about it. Apparently, if you add up the 2 smaller sides, then it HAS to be more than the biggest side.
Answer:
The third one
Step-by-step explanation:
5a-15+9a=3a+29
We simplify the equation to the form, which is simple to understand
5a-15+9a=3a+29
We move all terms containing a to the left and all other terms to the right.
+5a+9a-3a=+29+15
We simplify left and right side of the equation.
+11a=+44
We divide both sides of the equation by 11 to get a.
a=4