I need help on this maths question

Atriangle with all sides of equal length is a/an triangle. a. right b. scalene c. equilateral d. isosceles

1c) the number 131 is a term in the sequence defined by the explicit rule f(n)=5n-4. which term in the sequence is 131? 2a) write the first four terms of the function f(n)=n^2-1 2b) what is the 10th term of the sequence defined by the explicit rule f(n)=n^2-1 2c) the number 224 is a term in the sequence defined by the explicit rule f(n)=n^2-1. which term in the sequence is 224?

60 2(x + 2) in the diagram, gef and hef are congruent. what is the value of x?