Which expression can you simplify by combining like terms? 6d2 5cd-3dc 86d2 5cd-3dc 8 12c2-8d2c 3dc 412c2-8d2c 3dc 4 7d2-3c2 6d-c7d2-3c2 6d-c 16c2 8cd 7c-8d

The term like terms refer to terms with the same variables and that same variables are raised to the same exponent. In this problem or given for example, though it is not very clear because of the absence of the signs in the numerical coefficients, we can combine terms with d², cd and dc (should be the same, despite the rearrangement), c², d²c, c and d.