Question

1) Find the sum of 15 multiples of 8

Explanation
In detail

2) factorise

${x}^{2} + 10x - 5$
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Answer 1

Answer:

Ello!☺

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a)A.P=8,16,24,32...............

a=8,d=8

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As we know ,

Sn=n/2[2a+(n-1)d]

S15=15/[16+(15-1)8]

S15=960

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b)it is attached in statement

Answer 2

Step-by-step explanation:

$\fbox\color{Blue}{Hola Mate}$

The first 8 multiples of 8 are

8, 16, 24, 32, 40, 48, 56,64

Here:

a = 8

d = 8

$\red{S15 = 960}$

$\frac{n}{2} (2a + (n - 1)d = \\ \frac{15}{2} (16 + 14 \times 8) = \\ 15 \times 64 = 960$

Factorization:

${x}^{2} + 10x - 5 =$

Simplifying

x2 + 10x + -5 = 0

Reorder the terms:

-5 + 10x + x2 = 0

Solving

-5 + 10x + x2 = 0

Solving for variable 'x'.

Begin completing the square.

Move the constant term to the right:

Add '5' to each side of the equation.

-5 + 10x + 5 + x2 = 0 + 5

Reorder the terms:

-5 + 5 + 10x + x2 = 0 + 5

Combine like terms: -5 + 5 = 0

0 + 10x + x2 = 0 + 5

10x + x2 = 0 + 5

Combine like terms: 0 + 5 = 5

10x + x2 = 5

The x term is 10x. Take half its coefficient (5).

Square it (25) and add it to both sides.

Add '25' to each side of the equation.

10x + 25 + x2 = 5 + 25

Reorder the terms:

25 + 10x + x2 = 5 + 25

Combine like terms: 5 + 25 = 30

25 + 10x + x2 = 30

Factor a perfect square on the left side:

(x + 5)(x + 5) = 30

Calculate the square root of the right side: 5.477225575

Break this problem into two subproblems by setting

(x + 5)

5.47 and -5.47.

$<marquee>Hope this helps</p><p>$