Solving Equations

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100

Twice a variable added to four is 34

2x + 4 = 34

X = 15

200

The sum of twelve times de number of pets and five times the number of pets

12P + 5P

300

If 5 is subtracted from twice an unknown number, the difference is 13.

2X - 5 = 13

X = 9

400

$500 is shared between Andy and Becky. Andy’s share is $150 less than Becky’s share. Calculate the amount of each of their shares.

X + (X-150) = 500 

2X = 650

X = 325

X - 150 = 175

500

Aran bought a shirt and a pair of pants for $34.75. The pair of pants cost $9.75 more than the shirt. Calculate the cost of the shirt.

X + (X + 9.75) = 34.75

2X = 25

X = 12.5

X + 9.75 = 22.2

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100

Twice a variable subtracted by four is 34

2X - 4 = 32

200

The number of boys multiplied by the number of girls

B*G

300

The add of six and a number divided by 3 is 4 

(6 + X) / 3 = 4

400

The sum of the three angles of any triangle is 180°. If 3x, 4x, and 5x are the measures of the three angles of a triangle, calculate the measure of each angle of the triangle.

3X + 4X + 5X = 180

12X = 180 

X = 15 

3X = 45 

4X = 60

5X = 75

500

If 3 times a number is increased by 22, the result is 14 less than 7 times the number

3X + 22 = 7X -14

X = 9

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100

Triple a number added to eleven

3X + 11

200

Three times a number subtracted by 7 is 21

3X - 7 = 16

X = 3

300

The number of sisters plus the number of brothers

S + B

400

The perimeter of an equilateral triangle is 60 meters. How long is each side?

X + X + X = 60

3X = 60 

X = 20

500

A farmer cuts a 300 foot fence into two pieces of different sizes. The longer piece should be four times as long as the shorter piece. How long are the two pieces?

X + 4X = 300

5X = 300

X = 60

4X = 240

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100

Twice a number plus six

2X + 6

200

The sum of a number and 4 is multiplied by 16, then subtracted from 40

40 - 16 (X + 4)

300

Three times a number plus a new number

3X + Y

400

If 6 times a number is decreased by 6, the result is the same as when 3 times the number is increased by 12.

6X - 6 = 3X + 12

X = 2

500

$200 is shared between Bill and Ann. Ann’s share is $50 more than Bill’s share. Calculate the size of each of their shares.

X + (X + 50) = 200

2X = 150

X = 75

X + 50 = 125

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100

One number is 4 more than 5 times the same number  

x+4 = 5X

X = 1

200

Half the number of cards

X / 2

300

A 25-metre-long wire is cut into two pieces. One piece is 7 metres longer than the other. Find the length of each piece.

X + (X+7) = 25

2X = 18

X = 9

X + 7 = 16

400

13 minus the number of apples multiplied by 3

13 - 3X 

500

A number subtracted from 9 is equal to 2 times the number.

9 - X = 2X

X = 3