Solve for x.

x2 + 4x - 21 = 0

A.) -3,-7
B.) -3,7
C.) 3,-7
D.) 3,7

Any is very appreciated! (picture is provided below)not sure how to do this at all won't lie

This is about circle theorems. someone asap : (

Asequence has its first term equal to 4, and each term of the sequence is obtained by adding 2 to the previous term. if f(n) represents the nth term of the sequence, which of the following recursive functions best defines this sequence? (1 point) f(1) = 2 and f(n) = f(n − 1) + 4; n > 1 f(1) = 4 and f(n) = f(n − 1) + 2n; n > 1 f(1) = 2 and f(n) = f(n − 1) + 4n; n > 1 f(1) = 4 and f(n) = f(n − 1) + 2; n > 1 i will award !