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3 years ago

Select the expression equivalent to -81 x + 27.

Mathematics

1 answer:

MArishka [77]3 years ago

5 0

Answer:

B -9(9x-3)

Step-by-step explanation:

b/c -9(9x-3) means -9×9x-(-3)

= -81x+27

if you say why -(-3) is +27, I will say b/c negative times negetive it give us positive. and if you they why we don't add -81x and 27, I will say b/c they are not like terms.

like terms : are terms with the same variable and same exponent.

example:2x and 3x,5xy and 9yx and etc....

if it helpful ❤❤

THANK YOU

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HELP !! ASAP !!

Sedaia [141]

Answer:

The roots are;

x = (2 + i)/5 or (2-i)/5

where the term i is the complex number representing the square root of -1

Step-by-step explanation:

Here, we want to use the completing the square method to solve the quadratic equation;

f(x) = -5x^2 + 4x -1

Set the function to zero

0 = -5x^2 + 4x - 1

So;

-5x^2 + 4x = 1

divide through by the coefficient of x which is -5

x^2 - 4/5x = -1/5

We now take half of the coefficient of x and square it

= -2/5^2 = 4/25

add it to both sides

x^2 - 4x/5 + 4/25= -1/5 + 4/25

(x- 2/5)^2 = -1/5 + 4/25

(x - 2/5)^2 = -1/25

Take the square root of both sides

x - 2/5 = √( -1/25

x - 2/5 = +i/5 or -i/5

x = 2/5 + i/5 or 2/5 - i/5

7 0

3 years ago

Mr.Nolans code for his atm card us a 4 digit number.The digits of the code are prjme factors of 84 listed from least to greatest

vlada-n [284]

1,2,3,4,6,7,12,14,21,28,42,84 are the prime factors of 84.

Therefore, the first four primes are: 1,2,3,7 so Mr. Nolans code is 1237.

3 0

3 years ago

3^(x-2) = 5^(x+1)

Molodets [167]

Answer:

$x=log_{\frac{3}{5} }(45)$

$x-2=log_{3}(5)x+log_{3}(5) \\x-log_{3}(5)x=log_{3}(5)+2\\(1-log_{3}(5))x=log_{3}(5)+2\\x=\frac{log_{3}(5)+2}{1-log_{3}(5)} \\x=\frac{log_{3}(5)+log_{3}(3^2)}{log_{3}(3)-log_{3}(5)} \\x=\frac{log_{3}(5x3^2)}{log_{3}(\frac{3}{5} )} \\x=\frac{log_{3}(5x9)}{log_{3}(\frac{3}{5} )} \\x=\frac{log_{3}(45)}{log_{3}(\frac{3}{5} )}\\x=log_{\frac{3}{5}}(45)$