The Square of a positive number is 12 more than 4 times the number. Find the number. [ Only an algebraic solution will be accept
1 answer:
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Answer:
- r = 3V/(2πh²)
- h = 3V/b²
- r = 25/π cm ≈ 7.9577 cm
- w = 15 cm
Step-by-step explanation:
1. Multiply both sides of the equation by the reciprocal of the coefficient of r.
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2. Multiply both sides of the equation by the reciprocal of the coefficient of h.
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3. Solve the circumference formula for r, then substitute the given information.
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4. Solve the perimeter formula for width, the substitute the given information and do the arithmetic.
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In general, solving for a particular variable involves "undoing" what has been done to the variable, usually in the reverse order. In part 4, the variable W has L added and the sum is multiplied by 2. We "undo" those operations, last operation first, by dividing by 2 and subtracting L.
The properties of equality say you can do what you like to an equation as long as you do the same thing to both sides of the equation. So, when we say "divide by 2", we mean "divide both sides of the equation by 2." Likewise, "subtract L" means "subtract L from both sides of the equation."