An equilateral triangle has 3 equal sides by definition.
so we know that x+2 = -2x+20 because we're told that those are both lengths of the triangle's sides. let's solve for x.
x+2 = -2x + 20
add 2x to both sides.
3x + 2 = 20
subtract 2 from both sides.
3x = 18
divide both sides by 3.
x = 6
now, let's find the length of the sides. plug 6 into one side, which is x+2.
6+2 = 8. so each side's length must be equal to 8. let's just check to make sure we didn't make a mistake. if this is correct, then -2x + 20 should also = 8.
-2(6) + 20
-12 + 20
8.
so we know that the sides = 8. let's see if 14 - x or 2x+4 are equal to 8 when we plug in 6 for x.
14 - 6 = 8. so 14-x could be a length for a side.
2(6) + 4 = 12 + 4 = 16. so 2x + 4 can not be a length for a side.
the answer is 14 - x only, or C.
Answer:
N = 85
Step-by-step explanation:
(236 + 542)+N = 863
778 + N = 863
N = 863 - 778
N = 85
What does the variables represent?
in case you wonder why we used 105 as LCD,
21 = 3 * 7
15 = 3 * 5
the "3" is common to both denominators, so we "use it once" and our LCD is then 3 * 7 * 5.
