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Solve the simultaneous equations: 3x + y = 19 and x - 2y = -3

First rearrange x - 2y = -3 by adding 2y to each side to give x = -3 + 2ySubstitute this into the first eq. to give 3(-3 +2y) + y = 19Expand brackets first: -9 + 6y + y = 19Rearrange and simplify by collecti...
JM
Answered by Jessica M. • Maths tutor
5708 Views

y =(4x)/(x^2+5) (a) Find dy/dx, writing your answer as a single fraction in its simplest form. (b) Hence find the set of values of x for which dy/dx<0

dy/dx = 4/(x^2+5) - 4x(2x)/(x^2+5)dy/dx= 4(5-x^2)/(x^2+5)^2Part B4(5-x^2)/(x^2+5)^2&lt;05-x^2&lt;05&lt;x^2
DK
Answered by Dominic K. • Maths tutor
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Factorise f(x)=3x^3+8x^2-20x-16 completely

First we need to use the factor theorem to find a factor.f(1)=-25 so x-1 is not a factorf(-1)=9 so x+1 is not a factorf(2)=0 so x-2 is a factorSo x-2 is our starting point, we need to polynomial division f(x...
LB
Answered by Luke B. • Maths tutor
5867 Views

Solve the following simultaneous equations 7x - 6y =38 and 3x + 9y =-3

To solve these equations you first want to eliminate the same variable from each equation. In this question it is easiest to eliminate Y, to do this we will times equation 1 by 3 to get 21X-18Y=114 and equat...
IR
Answered by Isabelle R. • Maths tutor
3876 Views

Write 16*8^2x as a power of 2 in terms of x.

Change 16 as a power of 2 to get 2 4 . Change 8 2x as a power of 2 gives (2 3 ) 2x . You can times the two powers together giving 2 6x .So 16*8 2x =2 4 *2 6x . Now the powers can be added since the bases are...
NA
Answered by Nabeel A. • Maths tutor
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