Will mark brainiest if right!

factor completely.
x^2+4x−21

 (x +7)(x -3)

Step-by-step explanation:

The constants in the binomial factors must multiply to give -21 and must add to give +4. Since you're familiar with your multiplication tables, you know that ...

  -21 = -1·21 = -3·7 = -7·3 = -21·1

The sums of these factor pairs are 20, 4, -4, -20. Clearly the pair of choice is -3 and 7. Then the binomial factors are ...

  (x -3)(x +7)

y-1700=200(x+4)

step-by-step explanation:

200(x+4) is 200x + 800 she is saving 200 per week x is the weeks and the -1700 is. us that’s howmuch she already had

5   1/4   miles per hour

step-by-step explanation:

15   3/4 / 3 = 5   1/4