Question

Multiply: (5t – 4)(4t 5) What is the product? 20t2 9t – 20 20t2 18t – 19 20t2 25t – 36 20t2 41t – 20.

Answer 1

We can open the brackets and internal terms will multiply to other bracketed expression.

The product result of given expression is given by:

Option A: $20t^2 + 9t - 20$

Given that:

To find product result of $(5t - 4)(4t+ 5)$

Multiplication will go like this:

We can open the bracket of first expression and do further internal multiplication as:

$\begin{aligned}(5t - 4)(4t+ 5) &= 5t(4t+5) -4(4t+5)\\&= 5t \times 4t + 5t \times 5 - 4 \times 4t -4 \times 5\\&= 20t^2 + 25t -16t - 20\\&= 20t^2 + (25-16)t -20\text{\: (For like terms, coefficients combines)}\\&= 20t^2+ 9t - 20\end{aligned}$

(-4 times +5 is -20 since -1 times +1 is -1)

Thus, the product result is given by:

Option A: $20t^2+ 9t - 20$

Learn more about algebraic multiplication here:

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