Question

28. (5p – 6q )2 +60pq 29. 2(x + y )2 – 4xy 30. (3a – 7b )2 – 42ab

Answer 1

Ответ:

Объяснение:

28. (5p – 6q )² +60pq=25p²-60pq+36q²+60pq=25p²+36q²

29. 2(x + y )² – 4xy=2(x²+2xy+y²)-4xy=2x²+4xy+2y²-4xy=2x²+2y²

30. (3a – 7b )² – 42ab=9a²-42ab+49b²-42ab=9a²+49b²

Answer 2

It looks like you've provided three mathematical expressions, and it seems like you want to simplify them. I'll simplify each of these expressions for you:

28. (5p - 6q )^2 + 60pq To simplify this expression, first expand the square of the binomial:

(5p - 6q)^2 = 25p^2 - 60pq + 36q^2

Now, add 60pq to this expression:

25p^2 - 60pq + 36q^2 + 60pq

The -60pq and +60pq cancel each other out:

25p^2 + 36q^2

So, the simplified expression is 25p^2 + 36q^2.

29. 2(x + y)^2 - 4xy To simplify this expression, first expand the square of the binomial:

(x + y)^2 = x^2 + 2xy + y^2

Now, multiply this by 2:

2(x^2 + 2xy + y^2) = 2x^2 + 4xy + 2y^2

Finally, subtract 4xy from this expression:

2x^2 + 4xy + 2y^2 - 4xy

The 4xy and -4xy cancel each other out:

2x^2 + 2y^2

So, the simplified expression is 2x^2 + 2y^2.

30. (3a - 7b)^2 - 42ab To simplify this expression, first expand the square of the binomial:

(3a - 7b)^2 = 9a^2 - 42ab + 49b^2

Now, subtract 42ab from this expression:

9a^2 - 42ab + 49b^2 - 42ab

The -42ab and -42ab cancel each other out:

9a^2 + 49b^2

So, the simplified expression is 9a^2 + 49b^2.