Multiply.(2/5t-1)(3/5t+1)

= (6/25)t^2 + (2/5)t - (3/5)t - 1

= (6/5)t^2 - (1/5)t - 1

To multiply the expression (2/5t-1)(3/5t+1), you can use the distributive property of multiplication over addition/subtraction. It states that a(b+c) = ab + ac. Let's break it down step by step:

Step 1: Multiply the terms of the first parenthesis (2/5t-1) with the terms of the second parenthesis (3/5t+1).

(2/5t)(3/5t) + (2/5t)(1) + (-1)(3/5t) + (-1)(1)

Step 2: Simplify each term in the expression.

(6/25t^2) + (2/5t) + (-3/5t) + (-1)

Step 3: Combine like terms.

(6/25t^2) + (2/5t - 3/5t) - 1

Step 4: Simplify further, if possible.

(6/25t^2) - (1/5t) - 1

Thus, the simplified multiplication of (2/5t-1)(3/5t+1) is (6/25t^2) - (1/5t) - 1.