Her's the question 

Find the value of B in the equation

b² + 2 + 1/b²= 4

Let x = b²,

So we have x + 1/x = 2 [ subtract 2 from both sides]

Multiply both sides by x, this will give x² + 1 = 2x because x * 1/ x = 1

so we now have x² - 2x + 1 = 0 [ subtract 2x from both sides]

This equation has a well known answer: (x-1)(x-1) = 0 [ check your algebra book]

So x = 1, which means b² = 1, or b = 1

Check: 1 + 2 + 1/1 = 4

thank you very much ure too good, now i stil have another one, pleeaase,

here it is,

Factorise 9 - 4(a + b - c)²
thanks

Dis a difference of 2 squares problem
9-4(a+b-c)²
3²-2²(a+b+c)²
(3-2a-2b+2)(3+2a+2b-2c)

Thanks solomon vry much, there are still many other questions that are troubling me
like this one

Make t the subject of the formula

s = ut + 1/2at²

S=ut+1/2ut^2. Dis is quadra, equatn. Try nd use completing d square method. Surely, u will get 2 propective 4mular for 't'