what is the product?\n(9t - 4)(-9t - 4)\n-81t² - 16\n-81t² + 16\n-81t² - 72t + 16\n-81t² + 72t + 16

Explanation:

Step1: Use FOIL method

$(9t - 4)(-9t - 4)=9t\times(-9t)+9t\times(-4)+(-4)\times(-9t)+(-4)\times(-4)$

Step2: Calculate each product

$9t\times(-9t)=-81t^{2}$, $9t\times(-4)=-36t$, $(-4)\times(-9t) = 36t$, $(-4)\times(-4)=16$

Step3: Combine like - terms

$-81t^{2}-36t + 36t+16=-81t^{2}+16$

Answer:

$-81t^{2}+16$