How to factor completely: 15x²-40x-15

1 answer:

4 0

$15x^2-40x-15 =0\ \ /:5\\ \\3x^2-8x-3 =0 \\ \\a=3, \ b=-8 , \ c= -3 \\ \\\Delta =b^2-4ac =(-8)^2 -4\cdot 3\cdot (-3)=64+36=100 \\ \\x_{1}=\frac{-b-\Delta }{2a}=\frac{8-\sqrt{100}}{2 \cdot 3}=\frac{8-10}{6}=-\frac{2}{6}=-\frac{1}{3}$

$x_{2}=\frac{-b+\Delta }{2a}=\frac{8+\sqrt{100}}{2 \cdot 3}=\frac{8+10}{6}= \frac{18}{6}=3\\ \\ 3x^2-8x-3 = 3(x+\frac{1}{3})(x-3)=(3x+1)(x-3) \\ \\ \\Answer : \ 15x^2-40x-15 = 3x^2-8x-3 =(3x+1)(x-3)$

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rosa and brett are the only two people in a school election. rosa got 314 votes in the election. she got 18 more votes then bret

elena-s [515]

Answer:

See explantion

Step-by-step explanation:

Given

$Rosa = 314$

$Brett = 18\ more$

The question is incomplete as what is required is missing from the question. I'll solve on a general term

A possible question is: Determine the total number of votes by Brett

We have that:

$Brett = 18\ more$

So:

$Brett = 18 + Rosa$

Substitute 314 for Rosa

$Brett = 18 + 314$

$Brett = 332$

Another possible question is: Determine the total number of voters.

This is done by:

$Total = Brett + Rosa$

$Total = 332 + 314$

$Total = 646$

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Check the picture below.

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