Daily Practice - Higher Plus

The point (9, 40) lies on the circle x² + y² = 1681. Work out the gradient of the tangent to the circle at that point.The point (9, 40) lies on the circle x^2 + y^2 = 1681. Work out the gradient of the tangent to the circle at that point.

A bag holds 3 red, 5 blue and 3 green counters. Two are taken without replacement. Given neither is green, what is the probability both are red?

On a histogram, a 4-wide bar and a 16-wide bar have the same frequency density of 2.5. How many more values are in the wider class?

Expand and simplify (3 + √10)(3 - √10).Expand and simplify (3 + sqrt(10))(3 - sqrt(10)).

Solve x² + y² = 225 and y = x - 3 simultaneously.Solve x^2 + y^2 = 225 and y = x - 3 simultaneously.