Question

(7c+3)(7c-3) Алгебра, 7 класс

Answer 1

(7c+3)(7c-3)=49c^2-21c+21c-9=49c^2-9

Answer 2

To simplify the expression (7c + 3)(7c - 3), you can use the FOIL method, which stands for First, Outer, Inner, Last. It's a technique for multiplying two binomials. Here's how you do it:

(7c + 3)(7c - 3)

Step 1: Multiply the First terms in each binomial: 7c * 7c = 49c^2

Step 2: Multiply the Outer terms in each binomial: 7c * (-3) = -21c

Step 3: Multiply the Inner terms in each binomial: 3 * 7c = 21c

Step 4: Multiply the Last terms in each binomial: 3 * (-3) = -9

Now, combine all the results:

49c^2 - 21c + 21c - 9

Notice that the middle terms, -21c and 21c, will cancel each other out.

The simplified expression is:

49c^2 - 9

So, (7c + 3)(7c - 3) simplifies to 49c^2 - 9.