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ForA=2x^2 –18x+80 (i) find dA/dx , (ii) find the value of x for which A is a minimum

dA/dx = 4x -18 : multiply the number before the x (coefficient) by the power and minus 1 from the power.4x = 18 so x = 4.5 to find the minimum or maximum point, make the differential equal to 0 and solve for...
DA
Answered by Dan A. • Maths tutor
6774 Views

Solve x^3+20x^2=125x

The expression can be rearranged to equal 0 by taking the 125 to the other side. To do this the opposite thing has to be done, so 125 must be subtracted to get x^3+20x^2-125=0 . All parts in this function in...
IZ
Answered by Isabella Z. • Maths tutor
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Expand (2x + 3)(x - 1)

everything in the first bracket should be multiplied by everything in the second individually. Then you should combine common factors to find the final answer.Starting with the first part of the 1st bracket ...
SM
Answered by Sahil M. • Maths tutor
10775 Views

the line L goes through the points A (3,1) and B(4,-2). Find the equation for L.

First we need to consider what a straight line looks like: y = mx + c (if we get something different we've gone wrong somewhere)one way to get the equation is using a point (general point is (x 1 , y 1 ) ), ...
WM
Answered by Will M. • Maths tutor
10183 Views

The curve y = 4x^2 + a/x +5 has a stationary point. Find the value of the positive constant 'a' given that the y-coordinate of the stationary point is 32. (OCR C1 2016)

First, we must find the value of x that corresponds to the stationary point, i.e. where the gradient (dy/dx) is zero. This will be in terms of 'a' (if we change 'a,' we change the shape of the function by a ...
JW
Answered by Jayden W. • Maths tutor
6018 Views