The triangle Sum Theorem says that the sum of all the angles in a triangle has to equal 180 degrees. Since all three sides (and, consequently, angles) in an equilateral triangle are the same, you can divide 180 by 3 to find the measure of any angle of an equilateral triangle (60 degrees).
When you divide numbers, you make the value smaller. So subtract the exponents will make the value with that base smaller.
5x + 2(x + 1) ≤ 23
Distribute the 2.
5x + 2x + 2 ≤ 23
Combine like terms.
7x + 2 ≤ 23
Subtract 2 from both sides.
7x ≤ 21
Divide both sides by 7
x ≤ 3
C is the answer hope this helps.