Question

Раскрыть скобки (3a-7c)^2

Answer 1

(3a-7c)²=9a²-42ac+49c²

Answer 2

To expand the expression $(3a - 7c)^2$, you'll need to apply the square of a binomial formula. The formula is:

$(a - b)^2 = a^2 - 2ab + b^2$

In this case, $a = 3a$ and $b = 7c$. Now, let's expand the expression:

$(3a - 7c)^2 = (3a)^2 - 2(3a)(7c) + (7c)^2$

Now, simplify each term:

1. $(3a)^2 = 9a^2$ (square of a binomial: $(a - b)^2 = a^2 - 2ab + b^2$)
2. $-2(3a)(7c) = -42ac$ (multiply the coefficients and add the exponents)
3. $(7c)^2 = 49c^2$ (square of a binomial: $(a - b)^2 = a^2 - 2ab + b^2$)

Putting it all together:

$(3a - 7c)^2 = 9a^2 - 42ac + 49c^2$