(x + 3)^2 - 4x^2 Factorise using the difference of two squares

Mathematics

1 answer:

AlladinOne [14]3 years ago

8 0

Answer:

3(x + 1)(3 - x).

Step-by-step explanation:

(x + 3)^2 - 4x^2

Using the identity a^2 - b^2 = (a - b)(a + b), we have

(x + 3 - 2x)(x + 3 + 2x)

= (-x + 3)(3x + 3)

= 3(x + 1)(3 - x)

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The mean score of 8 players is 14.5. If the highest individual score is removed the mean of the score of the remaining 7 players

AfilCa [17]

Answer:

The highest score is 32.

Step-by-step explanation:

We are given the following in the question:

The mean score of 8 players is 14.5.

Let x denote the highest score.

If x is removed, the mean of the score of the remaining 7 players is 12.

Formula for mean:

$\bar{x} = \dfrac{\displaystyle\sum x_i}{n}$

Putting values, we get:

$14.5 = \dfrac{\displaystyle\sum x_i}{8}\\\\\Rightarrow \displaystyle\sum x_i = 116\\\\12 = \dfrac{\displaystyle\sum y_i}{7}\\\\\Rightarrow \displaystyle\sum y_i = 84\\\\\displaystyle\sum y_i = \displaystyle\sum x_i -x \\\\84 = 116 - x\\\Rightarrow x = 32$