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3 years ago

Multiply (2 – 7i)(–1 + 4i). 26 + 15i –2 – 28i 26 + i –30 + 15i

Mathematics

2 answers:

vaieri [72.5K]3 years ago

8 0

Answer: its 26+15i

Step-by-step explanation:

on e2020

DENIUS [597]3 years ago

3 0

(2 - 7 i) (-1 + 4 i).26 - (32 + 697 i)

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Sierra borrows $310 from her brother to buy a lawnmower. She will repay $85 to

Ivanshal [37]

310-85=225
225/25=9
Therefore it will take her 9 weeks

8 0

2 years ago

Which are the solutions of x2 = 19x + 1?

Finger [1]

Answer:

$(\frac{19-\sqrt{365}} {2},\frac{19+\sqrt{365}} {2})$

Step-by-step explanation:

we have

$x^2=19x+1$

we know that

The formula to solve a quadratic equation of the form

$ax^{2} +bx+c=0$

is equal to

$x=\frac{-b\pm\sqrt{b^{2}-4ac}} {2a}$

in this problem we have

$-x^{2}-19x-1=0$

$a=1\\b=-19\\c=-1$

substitute in the formula

$x=\frac{-(-19)\pm\sqrt{-19^{2}-4(1)(-1)}} {2(1)}$

$x=\frac{19\pm\sqrt{365}} {2}$

$x=\frac{19+\sqrt{365}} {2}$

$x=\frac{19-\sqrt{365}} {2}$

$(\frac{19-\sqrt{365}} {2},\frac{19+\sqrt{365}} {2})$

therefore

StartFraction 19 minus StartRoot 365 EndRoot Over 2 EndFraction comma StartFraction 19 + StartRoot 365 EndRoot Over 2 EndFraction

6 0

2 years ago

Read 2 more answers

10÷652.3 please help me

professor190 [17]

Answer:

0.01533036946190

Step-by-step explanation:

10÷652.3

0.01533036946190

6 0

2 years ago

Read 2 more answers

Round to the merest hundredth389.993

kvasek [131]

What's a hundredth?

it's like this:

0.01

so where is the hundred place in this number?

389.9<em>9</em>3

it's the 9 that i made boldface

so to round to this number we delete everything after it, asking ourselves if the number after it is 4 or less? yes! so we can just delete it without changing anyway

389.99

3 0

2 years ago

Which of the following is NOT a variation of a Pythagorean identity?

Ipatiy [6.2K]

The expression that is not a variation of the Pythagorean identity is the third option.

<h3>What is the Pythagorean identity?</h3>

The Pythagorean identity can be written as:

$sin^2(x) + cos^2(x) = 1$

For example, if we subtract cos^2(x) on both sides we get the second option:

$sin^2(x) = 1 - cos^2(x)$

Which is a variation.

Now, let's divide both sides by cos^2(x).

$sin^2(x)/cos^2(x) + cos^2(x)/cos^2(x) = 1/cos^2(x)\\\\tan^2(x) + 1 = sec^2(x)\\\\tan^2(x) - sec^2(x) = -1$

Notice that the third expression in the options looks like this one, but the one on the right side is positive. The above expression is in did a variation of the Pythagorean identity, then the one written in the options (with the 1 instead of the -1) is incorrect, meaning that it is not a variation of the Pythagorean identity.

Concluding, the correct option is the third one.

If you want to learn more about the Pythagorean identity, you can read:

brainly.com/question/24287773

3 0

2 years ago