(z^2+6z)+14(z^2+6z)+45=0
1. Multiply out
z^2 + 6z + 14z^2 + 84z + 45 = 0
2. Combine like terms
15z^2 + 90z + 45 = 0
3. Use quadratic equation to get both answers for z.
z^2 + 6z + 14z^2 + 84z + 45 = 0
2. Combine like terms
15z^2 + 90z + 45 = 0
3. Use quadratic equation to get both answers for z.