Practice China questions with answers and explanations.
Subtract 7 from both sides and divide by 3: x = (10-7)/3 = 1.
By Vieta’s formula, the sum of the roots equals the coefficient 19.
aₙ=a₁+(n−1)d=6+(15−1)×5=76.
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 3 favourable outcomes out of 9 equally likely outcomes, so P(red)=3/9.
The coordinate differences are 3 and 4, so the distance is √(3²+4²)=5.
f′(x)=6x²+4x. Substituting x=2 gives 32.
An antiderivative is 2/2 x²+2x. At x=3, the value is 15.0.
The dot product is 2×2+3×4=16.
Percentage=(5/40)×100=12.50.
Subtract 6 from both sides and divide by 2: x = (28-6)/2 = 11.
By Vieta’s formula, the sum of the roots equals the coefficient 16.
