1,845 views
19 votes
19 votes
Please help with explanation

Please help with explanation-example-1
User Garrett Vlieger
by
2.3k points

2 Answers

18 votes
18 votes

Answer:

c) 81x² + 49x²y² - 126x²y

Explanation:

when you square something you are multiplying it by itself

(9x - 7xy)² = (9x - 7xy) (9x - 7xy)

this requires the FOIL method:

F = first = (9x)(9x) = 81x²

O = outer = (9x)(-7xy) = -63x²y

I = inner = (-7xy)(9x) = -63x²y

L = last = (-7xy)(-7xy) = 49x²y²

the two middle terms can be combined because they are 'like'

-63x²y + -63x²y = -126x²y

answer:

81x² - 126x²y + 49x²y²

the order is normally changed to be put in decreasing exponent order so 49x²y² is put before -126x²y

User Tonyhb
by
3.0k points
18 votes
18 votes

Answer:

C

Explanation:

use the formula = a² + 2ab + b²

(9x)² - 2 * 9x * 7xy + (7xy)²

81x² + 49x²y²- 126x²y

User Piotr Kula
by
3.0k points