Question

if x(x-1)=5 then the value of (x+2)² + 1/(x+2)² is​

Answer 1

Answer:

2 (x - 2)^2 = 18

2 (x^2 -4x +4) = 18

2x^2 - 8x + 8 = 18

2x^2 - 8x + 8 - 18 = 0

2x^2 - 8x - 10 = 0

2 (x^2 - 4x - 5) = 0

x^2 - 4x - 5 = 0

Using the cross method*

1 ………... -5 / -5

1 …………. 1 / 1

………………/ -4

Therefore:

x - 5 = 0 … x + 1 = 0

x = 5 … … x = -1

USING THE CROSS METHOD:

Because 1 multiplied by 1 gives 1 (the left two numbers multiply to give the number behind the x^2)

Also -5 multiplied by 1 gives -5 (the right two numbers multiply to give the constant of the equation)

Next, multiply the top left and bottom right numbers to give you 1 in this case

And, multiply the top right and bottom left numbers to give you -5 in this case

Add them together and you should get the number before the x (in this case -5 + 1 = -4)

Step-by-step explanation:

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