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3 years ago

If ln(x^2-x-1)=0 , then x= ?

Mathematics

1 answer:

Umnica [9.8K]3 years ago

3 0

Answer:

x = -1 or 2

Step-by-step explanation:

Taking the antilog, you have the quadratic ...

x^2 -x -1 = 1

x^2 -x -2 = 0 . . . . subtract 1

(x -2)(x +1) = 0 . . . factor

The values of x that make these factors zero are the solutions to the equation.

x = 2 or x = -1

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Four times a number decreased by seven

Elden [556K]

In order to answer this question, we must break this mathematical expression up into a series of mathematical operations (exponent, multiplication,division, addition, and/or subtraction):

"4 times a number" - The word "times" implies that we have to multiply 4 by an unknown number. We can simply label this unknown number as x.
"cubed" - In order to "cube" a number, we must raise it to the third power, or have an exponent of 3. Our unknown number of x now becomes x3 because we raised it to the third power.
"decreased by 7" - The word "decreased" implies that we must subtract 7 from the product of 4 multiplied by x3

With all of the information we now have, we can form an algebraic expression for this problem.
"4 times a number cubed decreased by 3" now becomes:
4x3 - 7

7 0

3 years ago

A school paid $31.25 for each calculator.

Sonja [21]

Answer:

500/31.25=16

Step-by-step explanation:

The school bought 16 calculators

4 0

2 years ago

The number of seats in a row has been increased at a rectangular-shape movie theater after renovation so that it is now five mor

Damm [24]

Let the number of rows be = r

Let the number of seats per row be = s

we know that the number of seats is 126.

So, $s\times r=126$ ..... (1)

As given, there are five more seats per row than the number of rows, so we can say that:

$s=r+5$

Putting this in equation (1)

$(r+5)*r=126$

$r^{2}+5r=126$

$r^{2}+5r-126=0$

$r^{2}+14r-9r-126=0$

$(r+14)(r-9)=0$

r=-14 and r=9 (neglecting the negative value) we get r=9

And s=r+5

so, s =9+5=14

Hence, there are 5 rows and 14 seats per row.

4 0

3 years ago

Examine each number. What number can you add to this number to make a number that has a whole-number square root?

Fantom [35]

the answer is 470

Step-by-step explanation:Because 470+470 which equals 940 and the square root is 30

3 0

3 years ago

When factoring a polynomial in the form ax2 + bx + c, where a, b, and c are positive real numbers, should the signs in the binom

gtnhenbr [62]

When factoring a polynomial in the form ax2 + bx + c, where a, b, and c are positive real numbers, the signs in the binomials should be both positive

<h3>What are quadratic equations?</h3>

Quadratic equations are second-order polynomial equations and they have the form y = ax^2 + bx + c or y = a(x - h)^2 + k

<h3>How to determine the true statement?</h3>

The form of the polynomial is given as:

ax2 + bx + c

Where a, b, and c are positive real numbers.

Since a, b, and c are positive real numbers. then the form of the expansion would be:

ax2 + bx + c = (dx + e)(fx + g)

<h3>Example to verify the claim</h3>

Take for instance, we have the following quadratic equation

x^2 + 6x + 8

Expand the equation

x^2 + 6x + 8 = x^2 + 4x + 2x + 8

Factorize the equation

x^2 + 6x + 8 = (x + 2)(x + 4)

Hence, the signs in the binomials should be both positive