23, because it is a prime number and therefore cannot be simplified enough to take outside of the square root.
6/x= -2/18
Cross multiply. ( Multiply the numerators together ) . ( Multiply the denominators together (.
6*18= - 2*x
108= -2x
Divide by -2 for 108 and -2x
108/-2= -2x/2
x= -54
Answer: x= -54
D it's store d, it's the cheapest