Answer:
1.75k-3.5
Explanation:
First, you should combine 1.5k and .25k, because while the coefficients are different, you can add them because they are being multiplied by the same variable, k. Like terms are terms in an expression or equation that share the same variables AND exponents, and in this case, with the shared variable being k and the exponent (1) also matched, you can do simple addition, adding 1.5 and 0.25 to get 1.75, and therefore 1.75k. As for the -3.5, it does not share any variables with other terms, so leave it be.