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3 years ago

How do I do this? -2(6-r)=4

Mathematics

2 answers:

iren [92.7K]3 years ago

6 0

To solve this, you need to isolate/get the variable "r" by itself in the equation:

-2(6 - r) = 4 Divide -2 on both sides

$\frac{-2(6-r)}{-2} =\frac{4}{-2}$

6 - r = -2 Subtract 6 on both sides

6 - 6 - r = -2 - 6

-r = -8 Divide -1 on both sides to get "r" by itself

$\frac{-r}{-1}=\frac{-8}{-1}$ (two negative signs cancel each other out and become positive)

r = 8

PROOF

-2(6 - r) = 4 Substitute/plug in 8 into "r"

-2(6 - 8) = 4

-2(-2) = 4

4 = 4

Tcecarenko [31]3 years ago

5 0

Answer:r=8

Step-by-step explanation:

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How much is half of 2.893

borishaifa [10]

2.893/2 = 1.4465 Pretty much it

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3 years ago

Given: △ABC, m∠A=60°, m∠C=45°, AB=9 Find: Perimeter of △ABC, Area of △ABC

stellarik [79]

Answer:

Perimeter of ΔABC: $\frac{27}{2}$ + $\frac{9}{2} * \sqrt6$ units

Area of ΔABC: $\frac{81}{8}*\sqrt3 + \frac{243}{8}$ units

Skills required: HS Geo, Special Triangles

Step-by-step explanation:

1) The best option is to break down this triangle. Let's draw an altitude from Point B down to Segment AC. The point from the altitude that intersects AC is Point D. BD is the height of our triangle, AC is the base.

2) Angle A is 60 degrees, and since Angle BDA is 90 degrees, Angle ABD is 30 degrees. We can use the 30-60-90 degree right triangle property for the triangle BDA.

This states that if the side opposite the 30 degree angle is $x$ , the side opposite the 60 degree angle is $x*\sqrt3$ , and the side opposite the 90 degree angle is $2x$ .

AB is 9 units, and it is opposite the 90 degree angle. This means that $2x=9, x = \frac{9}{2}$ ==> This then means that AD, the segment opposite the 30 degree angle in this triangle is $\frac{9}{2}$ units. Segment BD (the height) is $\frac{9}{2} * \sqrt3$ .

3) Angle C is 45 degrees, and Angle BDC is 90 degrees, which means that Angle CBD is 45 degrees. We can use the 45-45-90 degree right triangle property for the triangle BCD.

This states that if the side opposite the 45 degree angle is $x$ , the other side opposite a 45 degree angle is also $x$ , but the hypotenuse (side opposite the right (90 degree) angle) is $\sqrt{2}*x$ .

BD is $\frac{9}{2} * \sqrt3$ , which means DC is the same. BC, which is the hypotenuse is BD multiplied by square-root-2, which is $\frac{9}{2} * \sqrt6$ .

4) Area is $\frac{1}{2}*b*h$ , the base (b) is AC (which is $\frac{9}{2}+\frac{9}{2}*\sqrt3$ ), the height is BD ( $\frac{9}{2}*\sqrt3$ ). When multiple you will get $\frac{81}{4}*\sqrt3 + \frac{243}{4}$ , then this multiplied by 1/2 is

$\frac{81}{8}*\sqrt3 + \frac{243}{8}$ <--> this is the area!

5) Perimeter is just the sum of all side: 9 + $\frac{9}{2}$ + $\frac{9}{2} * \sqrt6$ = $\frac{27}{2}$ + $\frac{9}{2} * \sqrt6$ unit

6 0

3 years ago

Find the value of the variable and YZ if Y is between X and Z

PIT_PIT [208]

If point Y is between points X and Z, then

XY + YZ = XZ

In words, the distance from X to Y, plus the distance from Y to Z, is equal to the distance from X to Z. (See the attached picture.)

So 6b + 8b = 175

Can you finish it?