**Weegy:** 3xy cannot be combined with 2x - 5x x because it is different from the other terms.

**User:** A triangle has one side that measures 9 units, another side that measures x, and a third side that measures 2 units more than x. The perimeter is 29 units.
Which equation would we use to find the value of x?
x + x + 2 = 29
x + x + 2 + 9 = 29
x + x + x + 2 = 29
x + x + x + 2 + 9 = 29

**Weegy:** x + x + 2 + 9 = 29

**User:** When simplified, which of the following expressions has a coefficient of 5?
-4x - 9x
-4x + 9x
4x - 9x
4x - (-9x)

**Weegy:** The answer is =45x^3+12x^2 -7 -18x^3 +54x^2 -3
take the like terms together and simplify
45x^3-18x^3 +12x^2+54x^2 -7-3
=> (45-18)x^3 + (12+54)x^2 -(7+3)
=> 27x^3 + 66x^2 -10

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