Mathematics, 07.03.2021 04:30 lanakay2006

X^2+10x-88=8
where is the mistake and what should be done differently?

X^2+10x-88=8where is the mistake and what should be done differently?

Answers: 2

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Answer from: carbpotatoes

Step-by-step explanation:

a) There's a mistake at the third step from the beginning.

b) Instead of adding 25 , Josh added 100. While solving an equation using "Completing Squares Method" , we need to write the L.H.S. in the form of $a^{2} + 2ab + b^{2}$ or $a^{2} - 2ab + b^{2}$ , so that in the next step it can be converted into $(a + b)^{2}$ or $(a - b)^{2}$ .

c) $x^{2} + 10x - 88 = 8$

Taking -88 to R.H.S. , it's sign changes and becomes +88.

= x^2 + 10x = 88 + 8 = 96

Using "Completing Squares Method" , L.H.S. can be written as :-

$(x)^{2} + 2 \times x \times 5 + (5)^{2} = 96 + (5)^{2}$

$= (x + 5)^{2} = 96 + 25 = 121$

$= x + 5 = \sqrt{121} = -11 \: or +11$

$= x = +6 \: or -16$

Answer from: Quest

(2 x^3 + 7 x^2 + 5 x + 2)/(x (x + 2))

step-by-step explanation:

simplify the following:

x/x^2 + 3 x + 2 - (x (x + 1))/(x + 2)

combine powers. x/x^2 = x^(1 - 2):

x^(1 - 2) + 3 x + 2 - (x (x + 1))/(x + 2)

1 - 2 = -1:

x^(-1) + 3 x + 2 - (x (x + 1))/(x + 2)

put each term in 1/x + 3 x + 2 - (x (x + 1))/(x + 2) over the common denominator x (x + 2): 1/x + 3 x + 2 - (x (x + 1))/(x + 2) = (x + 2)/(x (x + 2)) + (3 x^2 (x + 2))/(x (x + 2)) + (2 x (x + 2))/(x (x + 2)) - (x^2 (x + 1))/(x (x + 2)):

(x + 2)/(x (x + 2)) + (3 x^2 (x + 2))/(x (x + 2)) + (2 x (x + 2))/(x (x + 2)) - (x^2 (x + 1))/(x (x + 2))

(x + 2)/(x (x + 2)) + (3 x^2 (x + 2))/(x (x + 2)) + (2 x (x + 2))/(x (x + 2)) - (x^2 (x + 1))/(x (x + 2)) = ((x + 2) + 3 x^2 (x + 2) + 2 x (x + 2) - x^2 (x + 1))/(x (x + 2)):

(2 + x + 3 x^2 (x + 2) + 2 x (x + 2) - x^2 (x + 1))/(x (x + 2))

3 x^2 (x + 2) = 3 x^3 + 6 x^2:

(2 + x + 3 x^3 + 6 x^2 + 2 x (x + 2) - x^2 (x + 1))/(x (x + 2))

2 x (x + 2) = 2 x^2 + 4 x:

(2 + x + 6 x^2 + 3 x^3 + 2 x^2 + 4 x - x^2 (x + 1))/(x (x + 2))

-x^2 (x + 1) = -x^2 - x^3:

(-x^2 - x^3 + 3 x^3 + 6 x^2 + 2 x^2 + 4 x + x + 2)/(x (x + 2))

grouping like terms, 3 x^3 - x^3 + 6 x^2 + 2 x^2 - x^2 + 4 x + x + 2 = (3 x^3 - x^3) + (6 x^2 + 2 x^2 - x^2) + (x + 4 x) + 2:

((3 x^3 - x^3) + (6 x^2 + 2 x^2 - x^2) + (x + 4 x) + 2)/(x (x + 2))

3 x^3 - x^3 = 2 x^3:

(2 x^3 + (6 x^2 + 2 x^2 - x^2) + (x + 4 x) + 2)/(x (x + 2))

6 x^2 + 2 x^2 - x^2 = 7 x^2:

(2 x^3 + 7 x^2 + (x + 4 x) + 2)/(x (x + 2))

x + 4 x = 5 x:

answer: (2 x^3 + 7 x^2 + 5 x + 2)/(x (x + 2))

Answer from: Quest

30 miles

step-by-step explanation:

we know that 60 seconds equals 1 minute and 60 minutes 1 hour

44 ft 60 sec 60 min 158400 ft

* * =

1 sec 1 min 1 hour hour

we know that there are 5280 ft per mile

158400 ft 1 mile 30 miles

* =

1 hour 5280 ft 1 hour

so in 1 hour it can travel 30 miles

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