Final answer:
To find the value of the expression 3x(80-x), we can use the distributive property and rearrange the equation to solve for x. The value of x is 80 or x = 0.
Step-by-step explanation:
To find the value of the expression 3x(80-x), we can use the distributive property to multiply 3x by both terms within the parentheses. This gives us 240x - 3x^2. The expression is now in quadratic form, so we can rearrange it to solve for x by setting it equal to zero: 3x^2 - 240x = 0. We can factor out an x to get x(3x - 240) = 0. This means that either x = 0 or 3x - 240 = 0. Solving the second equation, we find that x = 80. Therefore, the value of x is 80 or x = 0.