And what does a = with a line through it mean ?

see explanation

Step-by-step explanation:

given

, x ≠ - 1

The x ≠ - 1 means that x cannot take the value of - 1 as this would make the denominator equal to zero which would make the fraction undefined.

Factor the numerator/ denominator

8x² - 8 = 8(x² - 1) ← factor out 8 from both terms

x² - 1 ← is a difference of squares, hence

8x² - 8 = 8(x - 1)(x + 1)

4x + 4 = 4(x + 1) ← factor out 4 from both terms

Thus the fraction now simplifies to

Cancel the 8 and 4 by 4 and cancel the factor (x + 1), leaving

=  2(x - 1) = 2x - 2 ← in the form ax + b

the largest number of the four options is 1.8 x 10-2

you have it in scientific notation.

1.80 x 10-6   = 0.00000180

1.80 x 10-4   = 0.000180 (bigger, or "less small", than the former one)

so

1.8 x 10-2       = 0.0180. as you see. the "less small", or the biggest one of them all.

as you have negative exponent, it means you are dividing 1.8 by 100 (i.e. moving the dot towards left, two times).

if you had positive exponent for the scientific notation, power of tenths, you would be multiplying times 100 (moving the dot towards right) as below:

1.8 x (10)2 = 180

so. if you have negative exponent in scientific notation, move the dot toward left. if it is positive, toward right as many times the exponent tells you.