What is the sum of 5 (-3.4k-7) (3k 21) =

I am assuming that the correct equation is 5 (-3.4k - 7) + (3k 21) to get the sum.

distribute multiplication:

5 (-3.4k) - 5 (7) + (3k*21) = 0

-17k - 35 + 63k = 0

Look for k:

-17k + 63k = 35

46k = 35

46k / 46 = 35 / 46

k = 0.76

Substitute k with 0.76

5 (-3.4k - 7) + (3k21) = 0

5[ (-3.4) (0.76) - 7] + [{ (3) (0.76) }21] = 0

5 (-2.584 - 7) + (2.28) (21) = 0

5 (-2.584) - 5 (7) + 47.88 = 0

-12.92 - 35 + 47.88 = 0

- 47.92 + 47.88 = 0.04