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2. Solve 3x+2x=33.

Solution Divide by 3,

2

Add (+2√T)', or ()', 2 + 3 + = 11+ = 100

Extract √,

Transpose,

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9

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9

(A)

(1)

(3)

Therefore,

Scholium 1.-When the coefficient of x is 1, the quantity to be added to both members to complete the square is the square of half the coefficient of x.

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Scholium 2.-When the equation is multiplied through by the coefficient of x2, the quantity to be added to both members is the square of half the coefficient of x in the typical equation. This method is generally the best, as it avoids all fractions above and below fourths.

4. Solve 2x2 + 3 x = 14.

Solution: Multiply by 4 × 2, 16 x2 + 24 x = 112

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1 - 3

Therefore,

Scholium 3.-When the equation is multiplied through by four times the coefficient of x2, the quantity to be added to both members is the square of the coefficient of x in the typical equation. This is called the Hindoo method of completing the square. It avoids all fractions, but often gives rise to very large whole numbers.

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3. Solution of Literal Affected Quadratics. Illustrations.-1. Solve x2+ax=b.

Solution: Complete the square,

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210. When an equation contains two and only two exponents of the unknown terms, and one of them is twice the other, it is said to have the quadratic form; as,

x+6x=16, ax + bx3 = c, or

(a + b x) + p (a + b x)3 = c.

211. Any equation having the quadratic form, whatever its degree, may be solved by any of the methods employed to solve an affected quadratic.

Illustrations.-1. Solve x + 6 x2 = 16.

Solution: Complete the square,

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(A)

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Extract √,

Transpose,

Extract √,

x= ±√2, or 2√2

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4

16. (x2 + 2 x)2 — 23 (x2 + 2 x) + 120 = 0

17. (x2 — 5 x)2 — 8 x2 + 40 x = 84

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