Final answer:
To simplify the expression 4.2t-5-6.5t, start by combining like terms. Combine the coefficients of the t terms to get -2.3t, and combine the constant terms to get -5. Therefore, the simplified expression is -2.3t - 5.
Step-by-step explanation:
To simplify the expression 4.2t-5-6.5t, start by combining like terms. The like terms in this expression are the terms with the variable t. We can add or subtract these terms since they have the same variable. Combine the coefficients of the t terms, which are 4.2 and -6.5: 4.2t - 6.5t = (4.2 - 6.5)t = -2.3t. Next, combine the constant terms -5 and 0 to get -5: -5. Therefore, the simplified expression is -2.3t - 5.