Choose the correct product of (5x − 3)(5x + 3).

25x2 + 30x + 9 my answer

Question

Choose the correct product of (5x − 3)(5x + 3).
 	
	25x2 + 30x + 9 my answer

mathstudent55 · Answer

Do you know FOIL?

anonymous · Answer

yes

mathstudent55 · Answer

Can you do it and show every step without combining like terms?

whpalmer4 · Answer

if the last two numbers have opposite signs, your answer must also have a negative sign for the last term...
$$(a+b)(a-b) = a^2+ab-ab-b^2$$

whpalmer4 · Answer

"last two numbers" being the constant terms in the product, namely "-3" and "+3"

anonymous · Answer

$$\left( 5x+3\left( 5x-3 \right) \right)=\left( 5x ^{2} \right)-\left( 3 \right)^{2}=25x ^{2   }-9$$

anonymous · Answer

k thanks

anonymous · Answer

$$\left( a+b \right)\left( a-b \right)=a ^{2}-b ^{2}$$

whpalmer4 · Answer

Learn to recognize that pattern, called a difference of squares.  Knowing it, you can instantly write the answer to this problem:
$$(5x-3)(5x+3) = (5x)^2 -(3)^2 = 25x^2-9$$
and you can also instantly factor $$25x^2-9 = (5x-3)(5x+3)$$