87 ÷ 4 how many are in each group? are there any left over?

What was discovered because of the changing phases of the moon? Please Help!!! Will Give Lots Of Points!

Answer:

Firstly, the moon keeps changing its shape with 4 distinct moon phases that depend on the position of the moon and also on the position of the Earth. The moon orbits around the planet Earth, and the Earth orbits around the Sun.

Step-by-step explanation:

5 0

2 years ago

Perform the indicated operations. Write the answer in standard form, a+bi.<br> 5-3i / -2-9i

Vsevolod [243]

$\huge \boxed{\mathfrak{Answer} \downarrow}$

$\large \bf\frac { 5 - 3 i } { - 2 - 9 i } \\$

Multiply both numerator and denominator of $\sf \frac{5-3i}{-2-9i} \\$ by the complex conjugate of the denominator, -2+9i.

$\large \bf \: Re(\frac{\left(5-3i\right)\left(-2+9i\right)}{\left(-2-9i\right)\left(-2+9i\right)}) \\$

Multiplication can be transformed into difference of squares using the rule: $\sf\left(a-b\right)\left(a+b\right)=a^{2}-b^{2}$ .

$\large \bf \: Re(\frac{\left(5-3i\right)\left(-2+9i\right)}{\left(-2\right)^{2}-9^{2}i^{2}}) \\$

By definition, i² is -1. Calculate the denominator.

$\large \bf \: Re(\frac{\left(5-3i\right)\left(-2+9i\right)}{85}) \\$

Multiply complex numbers 5-3i and -2+9i in the same way as you multiply binomials.

$\large \bf \: Re(\frac{5\left(-2\right)+5\times \left(9i\right)-3i\left(-2\right)-3\times 9i^{2}}{85}) \\$

Do the multiplications in $\sf5\left(-2\right)+5\times \left(9i\right)-3i\left(-2\right)-3\times 9\left(-1\right)$ .

$\large \bf \: Re(\frac{-10+45i+6i+27}{85}) \\$

Combine the real and imaginary parts in -10+45i+6i+27.

$\large \bf \: Re(\frac{-10+27+\left(45+6\right)i}{85}) \\$

Do the additions in $\sf-10+27+\left(45+6\right)i$ .

$\large \bf Re(\frac{17+51i}{85}) \\$

Divide 17+51i by 85 to get $\sf\frac{1}{5}+\frac{3}{5}i \\$ .

$\large \bf \: Re(\frac{1}{5}+\frac{3}{5}i) \\$

The real part of $\sf \frac{1}{5}+\frac{3}{5}i \\$ is $\sf \frac{1}{5} \\$ .

$\large \boxed{\bf\frac{1}{5} = 0.2} \\$

3 0

3 years ago

Solve for x. <br><br> x + 8 = -15

anygoal [31]

1. Subtract 8 from both sides
2. Simplify to get x= -23

5 0

3 years ago

A damsel is in distress and is being

Katen [24]

Answer:

30 feet

Step-by-step explanation:

Let x be the length of the ladder. Then, x cos(60) = 15

If we divide both sides by cos(60), then x = 30 feet.

6 0

3 years ago

Read 2 more answers

An athlete plans to run 3 miles. each lap around the school yard is 3/7 mile. how many laps will the athlete run?

Maksim231197 [3]

He will need to run 7 laps.

8 0

3 years ago