Top answers

expand and simplify (x+3)(x-7)

(x+3)(x-7) = (x x) + (x -7) + (x 3) + (3 -7) = x^2 - 7x + 3x - 21 = x^2 - 4x - 21 Key here is to ensure you multiply each term in one bracket by both in the other, and to keep careful track of the signs.
LP
Answered by Luke P. • Maths tutor
26312 Views

Find the x co-ordinates of the stationary points of the graph with equation y = cos(x)7e^(x). Give your answer in the form x = a +/- bn where a/b are numbers to be found, and n is the set of integers.

The stationary points on a curve of the form y=f(x) are where dy/dx = 0. To find dy/dx, differentiate using the product rule: dy/dx = 7e^x(d/dx(cosx)) + cosx(d/dx(7e^x)) = -sinx(7e^x) + cosx(7e^x). Now set d...
JS
Answered by Joseph S. • Maths tutor
7743 Views

How do I use Pythagoras' Theorem to calculate the hypotenuse of a triangle?

[use of board] So, Pythagoras' theorem states that a^2+b^2=c^2. Therefore, we need to mark the triangle with a, b &c. a and b do not matter, c must be the longest edge, that creates the diagonal. Put the...
CT
Answered by Cathy T. • Maths tutor
4247 Views

Triangle ABC is a triangle with a right angle at vertex B. Length BC = 6cm and angle A = 30 degrees. How long is length AC?

Draw the triangle. BC is opposite to the angle given and we need to find the hypotenuse. Using SOHCAHTOA, we must use sine. Rearrange to find hypotenuse and then put the numbers in. Length AC = 12cm
CC
Answered by Courtney C. • Maths tutor
3933 Views

The line AB has equation 5x + 3y + 3 = 0. The line AB is parallel to the line with the equation y = mx + c. Find the value of m.

I like to separate problems into small steps that are easy to follow. In this example these would be: STEP 1: make y the subject (meaning only y on the Left hand side - LHS); 3y = -5x - 3. STEP 2: divide by ...
HS
Answered by Harrison S. • Maths tutor
3745 Views