Senior-secondary mathematics task 86: The roots of x² − 12x + 20 = 0 are r and s. Enter r+s.
By Vieta’s formula, the sum of the roots equals the coefficient 12.
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By Vieta’s formula, the sum of the roots equals the coefficient 12.
Subtract 11 from both sides and divide by 3: x = (38-11)/3 = 9.
Percentage=(12/27)×100=44.44.
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Use the circle-area formula A = πr². Substituting r = 9 gives A = π × 9² = 81π.
Rewrite the value using base 5: 3125 = 5^5. Matching exponents gives x = 5.
The dot product is 4×3+4×2=20.
An antiderivative is 4/2 x²+3x. At x=5, the value is 65.0.
f′(x)=9x²+4x. Substituting x=4 gives 160.
The coordinate differences are 3 and 4, so the distance is √(3²+4²)=5.
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There are 4 favourable outcomes out of 8 equally likely outcomes, so P(red)=4/8.
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The sum is n(n+1)/2=10, so the mean is 10/4.
aₙ=a₁+(n−1)d=9+(12−1)×2=31.