2006-12-06 04:02:49 · 6 answers · asked by ME 3 in Science & Mathematics ➔ Mathematics
(x-8)(x+7)
2006-12-06 04:05:33 · answer #1 · answered by BAJ 3 · 1⤊ 0⤋
x² - x - 56 = (x - 8)(x + 7) = 0
This means that either (x - 8) = 0 or (x + 7) = 0
x - 8 = 0 --- Add 8 to both sides...
x = 8
x + 7 = 0 --- Subtract 7 from both sides...
x = -7
ANSWER: x = 8 or x = -7
CHECK:
(8)² - (8) - 56 = 0
64 - 8 - 56 = 0
56 - 56 = 0
0 = 0 --- Checks out...
(-7)² - (-7) - 56 = 0
49 + 7 - 56 = 0
56 - 56 = 0
0 = 0 --- Checks out...
2006-12-06 12:14:36 · answer #2 · answered by Anonymous · 1⤊ 0⤋
yeah - that's the answer - but how did you get there
the first part is easy 1x1
then factor 56 - looking for factors that are 1 apart
since the middle number is 1 also
and since both are subtracted - the larger number will be the - and the smaller the +
-8 times +7
(x-8)(x+7)
2006-12-06 12:10:31 · answer #3 · answered by tomkat1528 5 · 0⤊ 0⤋
first u have to factor the equation, the logic behind it is that u have to find 2 number that if u ADD them u get -1 (-x) and if u multiply u get -56. factoring x^2 is just one X on each side
(x-8)(x+7) = 0
so X = 8, -7 (x has two answers)
2006-12-06 12:09:00 · answer #4 · answered by gelal2003 2 · 1⤊ 0⤋
You can rewrite the equation as
(x+7)(x-8)=0
There are two possibilities:
x+7=0 and therefore x = -7 or:
x-8=0 and therefore x=8.
2006-12-06 12:37:57 · answer #5 · answered by telstar5035 2 · 0⤊ 0⤋
x=8
x=-7
2006-12-06 12:10:26 · answer #6 · answered by photojenny 2 · 0⤊ 0⤋