Higher Plus

The point (12, 16) lies on the circle x² + y² = 400. Work out the gradient of the tangent to the circle at that point.The point (12, 16) lies on the circle x^2 + y^2 = 400. Work out the gradient of the tangent to the circle at that point.

A bag holds 6 red, 6 blue and 6 green counters. Two are taken without replacement. Given neither is green, what is the probability both are red?

A histogram has two bars: one 10 units wide with frequency density 1.5, one 5 units wide with density 3. How many values in total?

Rationalise the denominator of 42/6, giving your answer in its simplest form.Rationalise the denominator of 42/sqrt(6), giving your answer in its simplest form.

Solve x² + 11x + 28 > 0.Solve x^2 + 11x + 28 > 0.