Practice China questions with answers and explanations.
Subtract 10 from both sides and divide by 2: x = (26-10)/2 = 8.
By Vieta’s formula, the sum of the roots equals the coefficient 17.
aₙ=a₁+(n−1)d=9+(12−1)×2=31.
Choose an option to check your answer.
The sum is n(n+1)/2=10, so the mean is 10/4.
Choose an option to check your answer.
There are 4 favourable outcomes out of 8 equally likely outcomes, so P(red)=4/8.
The coordinate differences are 3 and 4, so the distance is √(3²+4²)=5.
An antiderivative is 3/2 x²+2x. At x=4, the value is 32.0.
The dot product is 3×2+3×1=9.
Rewrite the value using base 4: 256 = 4^4. Matching exponents gives x = 4.
The coordinate differences are 3 and 4, so the distance is √(3²+4²)=5.
f′(x)=6x²+16x. Substituting x=3 gives 102.
The dot product is 2×4+2×6=20.
