Question

Find the square. (6m 7)^2 a. 36m^2 84m 49 b. 36m^2 84m – 49 c. 36m^2 42m – 49 d. 36m^2 – 84m 49

Answer 1

`(6m\pm7)^2=(6m)^2\pm2\cdot6m\cdot7+7^2=\boxed{36m^2\pm84m+49}\\\\Use:(a\pm b)^2=a^2\pm2ab+b^2`

Answer 2

Option a
`(6m+ 7)^2=36m^2+49+84m`

Option d
`(6m- 7)^2=36m^2+49-84m`

Explanation:

Given : Expression -
`(6m\pm7)^2`

To find : The square of the given expression

Solution :

We have to solve
`(6m\pm7)^2`

Apply property :
`(a\pm b)^2=a^2+b^2\pm 2ab`

In the given expression
`(6m\pm 7)^2`

a=6m, b=7

The solution is

`(6m+7)^2=(6m)^2+(7)^2\pm 2(6m)(7)`

`(6m+7)^2=36m^2+49\pm 84m`

Therefore,

If the sign is '+' then Option a is correct.

If the sign is '-' then Option d is correct.