Answer:
55.6%
Step-by-step explanation:
The fraction 90/162 in its decimal equivalent is 0. 556. Multiplying this by 100 yields the percentage 55.6%.
The rule for negative exponents is that if the exponent is negative to begin with, in order to make it negative, you put it into the denominator of a fraction, and raise it to whatever the power is. To go from positive exponents (those that are already in the denominator), move it up to the numerator and make the exponent negative. So your solution would be 5x^-2