Yes, the set <span>of people who wear expensive perfume is well-defined.</span><span> A set is said to be well-defined if its definition assigns it a unique value. Otherwise, the set is said to be not well-defined or ambiguous."W</span><span><span>ell-defined” means that any given object in the entire world, whether abstract or concrete is either an element of the set or isn't.</span> </span>
9x-7x= 2x
because both are x's now u cant add nor subtract anything to Y so just leave it alone but u can add 6+14
2x+8y=20
5x+7y=105
There are four variants are possible
1. You sold 15 adult tickets
2. You sold 7 student tickets and 10 adult tickets
3. You sold 14 student tickets and 5 adult tickets
4. You sold 21 student tickets.