Twice the sum of three and a number is 30. Find the number

9514 1404 393

Step-by-step explanation:

When x represents the number, "the sum of 3 and a number" is (x+3). Twice that sum is 2(x+3). "Is 30" means this expression is equal to 30:

  2(x +3) = 30 . . . . an equation for the given conditions

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We can solve this equation by dividing by 2:

  x + 3 = 15

  x = 12 . . . . . . subtract 3

The number is 12.

2x^2+5x+17

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