Search our library of Maths questions

Top answers

Maths

All levels

Find the stationary points on y = x^3 + 3x^2 + 4 and identify whether these are maximum or minimum points.

Differentiate wrt x. This leaves dy/dx = 3x^2 + 6x and equate this to 0 as we are looking for stationary points.So, 3x^2 + 6x = 0. Factorise to get x(3x +6) = 0. So x = 0 and x = -2 are the two solutions....

Answered by Tutor169411 D. • Maths tutor

2613 Views

Solve the simultaneous equations 3x +y =11 and 2x+y=8

Equation 1: 3x+y= 11, Equation 2: 2x+y=8. You want to find out what x is and what y is.In both equations there is only 1 unit of y therefore it is easiest to rearrange the first equation so that it equals...

Answered by Kathryn M. • Maths tutor

3836 Views

White paint costs £2.80 per litre and blue paint costs £3.50 per litre. White and blue paint are mixed in the ratio 3 : 2. How much does it cost to make 18 litres of this mixture?

18/(3+2)=3.63x3.6=10.8 2x3.6=7.210.8x2.8=30.247.2x3.5=25.230.24+25.2=55.44

Answered by David C. • Maths tutor

2639 Views

Solve the simultaneous equations: y-2x-4=0, 4x^2+y^2+20x=0

Re-arrange y-2x-4=0 to y=2x+4Substitute y=2x+4 into 4x^2+y^2+20x=0 to get 4x^2+(2x+4)^2+20x=0Expand the brackets to get 4x^2+(4x^2+16x+16)+20x=0Simplify to get 8x^2+36x+16=0Divide by 4 to get 2x^2+9x+4=0F...

Answered by Andrew H. • Maths tutor

6197 Views

Solve x^2=4(x-3)^2

expand the brackets to obtain x^2=4(x^2-6x+9)expand the brackets to obtain x^2=4x^2-24x+36rearrange to obtain 0=3x^2-24x+36factorise to obtain 0=(3x-6)(x-6)solve for x=6 or x=2

Answered by Edwin E. • Maths tutor

2706 Views