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3 years ago

5

R 2- 12r - 28 = 0

lt="r 2- 12r - 28 = 0" align="absmiddle" class="latex-formula">

1 answer:

Neko [114]3 years ago

5 0

Answer:

Step-by-step explanation:

r² - 12r - 28 = 0

r² - (14 - 2)r - 28 = 0

r² - 14r + 2r - 28 = 0

r ( r - 14 ) + 2 ( r - 14 ) = 0

( r - 14) ( r + 2 ) = 0

Either

r - 14 = 0

r = 14

or

r + 2 = 0

r = -2

therefore r = - 2 or 14

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