Answer:
Associative property
Step-by-step explanation:
Associative property allows you to put parenthesis in a part of the equation. We can only apply associative property on a part with multiplication or addition. If you do it with at an equation with subtraction or division you can change the result and make calculation mistake.
In this question, all of the operation used is multiplication. The result won't change even if you put parenthesis, both will give result of 480
Let x = amount invested at 8%
26000 - x = amount invested at 6%
0.08x + 0.06(26000 - x) = 1860
solving the equation you get x = 15000
and subtract that from 26000 you get 11000
8% investment = 15000
6% investment = 11000
I don't like these algebra problems which pretend to be geometry.
These are supplementary angles adding to 180 degrees; geometry done.
7x - 1 + 3x - 9 = 180
10 x = 190
x = 19
ABC=3x - 9 = 3(19) - 9 = 48
Answer 48°