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2(3x - 5) +4(5x+1) - (x+2) expand and multiply

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simmydim | eNotes Newbie

Posted May 18, 2013 at 9:11 AM via web

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2(3x - 5) +4(5x+1) - (x+2) expand and multiply

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llltkl | College Teacher | Valedictorian

Posted May 18, 2013 at 9:59 AM (Answer #1)

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2(3x-5)+4(5x+1)-(x+2)                (given)

Multiply the terms using distributive property and remove the brackets:

2*3x-2*5+4*5x+4*1-1*x-1*2

=6x-10+20x+4-x-2

Now arrange the like terms:

6x+20x-x-10+4-2

=25x-8

Hence, the required answer is 25x-8.

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simmydim | eNotes Newbie

Posted May 18, 2013 at 11:30 AM (Reply #1)

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can I ask why the +2 at the end of the equations becomes a -2 ?

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llltkl | College Teacher | Valedictorian

Posted May 18, 2013 at 12:30 PM (Answer #2)

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Here +2 is within the first bracket. When we are multiplying it by -1 and removing the bracket, we are not only multiplying the numbers but also their signs.  As per the rule of signs, a positive(+) sign multiplied by a negative(-) sign yields a negative(-) sign or two unlike signs make a negative sign. So, in the given problem +2 becomes -2.

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simmydim | eNotes Newbie

Posted May 18, 2013 at 12:33 PM (Reply #1)

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thanks that made it very clear

 

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