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Solve the simultaneous equations to find the values of x and y: 3x + 5y = -4 and 10x - 4y = -34

Firstly we need to remove one of the variables. We can use the fact that y has different signs to do this. 3x + 5y = -4 multiplied by 4 gives: 12x + 20y = -16 10x - 4y = -34 multiplied by 5 gives: 50x - 20y ...
TD
Answered by Tutor112326 D. Maths tutor
5756 Views

Differentiate y =cos^4(x)

Let u = cos xdu/dx = -sin xy = u 4 dy/du = 4u 3 dy/dx = dy/du * du/dx = (4u 3 ) * (-sin x) = 4 cos 3 x * -sin x = -4 cos 3 x sin x
CK
Answered by Christiyan K. Maths tutor
5011 Views

factorise and hence solve x^2 + 10x +18 = -3

x = -3 , x= -7
BW
Answered by Billy W. Maths tutor
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solve the following simultaneous equations 4x + 6y = 16 and x + 2y = 5

x = 1, y = 2
BW
Answered by Billy W. Maths tutor
4493 Views

Differentiate y=3x^2+2x+4 and find the stationary points, decide if it is a local maximum or minimum.

First Differentiate the equation to getdy/dx=6x+2Equal this to 0 to find the stationary pointdy/dx=0=6x+2 => 6x=-2=> x=-2/6=> x=-1/3 differentiate again to find the whether it is a maximum or minimu...
JG
Answered by Jemma G. Maths tutor
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