7 x (-2) = ? * what’s the answer

The difference of three and the reciprocal of a number is equal to the quotient of 20 and the number. find the number.

Y= a(x-3)squared-1 what is the value of a

Acentral angle measuring 160 degrees intercepts an arc in a circle whose radius is 4. what is the length of the arc the circle formed by this central angle? round the length of the arc to the nearest hundredth of a unit. a) 4.19 units b) 6.28 units c) 12.57 units d) 12.57 square units