Vivian L. answered • 03/10/14

Tutor

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Microsoft Word/Excel/Outlook, essay composition, math; I LOVE TO TEACH

Hi Celsey;

x(x+2)=7920

Distribute the x...

x

^{2}+2x=7920x

^{2}+2x-7920=0For the FOIL...

FIRST must be (x)(x)=x

^{2}OUTER and INNER must add-up to 2x.

LAST must be (90)(88) or (88)(90)...

(x+90)(x-88)=0

Either or both parenthetical equation(s) must equal zero...

x+90=0....................x-88=0

x=-90.......................x=88

room number cannot be negative. Second answer is only answer.

**Room numbers are 88 and (x+2), 90.**

Steve S.

03/11/14