21
18=0.86x - 0.09 Put 18 as the y value and solve for x
18.09=0.86x Add 0.09 on both sides.
21.03=x Then divide on both sides by 086
2√72 / √8 ± √2
If the denominator is √8 + √2,
2√72 / √8 + √2
= 2√(2*2*2*3*3) / √(2*2*2) + √2
= 2*2*3√2 / 2√2 + √2
= 12√2 / 3√2
= 4
Bone dry, sorry nothing I can do about that