Answer:

Step-by-step explanation:

Answer: 27x²yz + 3xz² - 2xy - 2y²z + 2yz²
<u>Step-by-step explanation:</u>
Use the distributive property.
3xz(9xy + z) - 2yz(x + y - z)
= 3xz(9xy) + 3xz(z) -2yz(x) -2yz(y) -2yz(-z)
= 27x²yz + 3xz² -2xy -2y²z +2yz²
15f -8f+ 13= 55
⇒ 7f+ 13= 55
⇒ 7f= 55- 13
⇒ 7f= 42
⇒ f= 42/7
⇒ f=6
Final answer: f=6~