Solve for x in the diagram below.
3a
80°
2z
د 2

x=20

Step-by-step explanation:

The 3 angles are on a straight line together. Therefore, they are supplementary. This means they must add to 180 degrees.

Therefore,

3x+80+2x=180

Combine like terms by adding 3x and 2x

(3x+2x)+80=180

5x+80=180

We want to find out what x is. In order to do this, we have to get x by itself. Perform the opposite of what is being done to the equation. Keep in mind, everything done to one side, has to be done to the other.

80 is being added to 5x. The opposite of addition is subtraction, so subtract 80 from both sides.

5x+80-80=180-80

5x=180-80

5x=100

x is being multiplied by 5. The opposite of multiplication is division, so divide both sides by 5.

5x/5=100/5

x=100/5

x=20

x is equal to 20.

x = ±sqrt(10)

step-by-step explanation:

5 - 2x² = -15

subtract 5 from each side

5-5 - 2x² = -15-5

-2x^2   = -20

divide by -2 on each side

-2x^2   /-2= -20/-2

x^2 =10

take the square root on each side

sqrt(x^2 )=±sqrt(10)

x = ±sqrt(10)

check:

5 - 2x² = -15

+sqrt(10)

5 - 2(sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15

-sqrt(10)

5 - 2(-sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15

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