I need to distribute the 3 to each term inside the parentheses. This means I have to multiply 3 by 8x^2, then by -2x, then by 1. To multiply 3 by 8x^2, I multiply the coefficients and keep the exponent, so I get 24x^2. To multiply 3 by -2x, I multiply the coefficients and keep the exponent, so I get -6x. To multiply 3 by 1, I just get 3. So the final expanded expression is 24x^2-6x+3. 
Expand the following expression: $3(8x^2-2x+1)$.