Answer:
19- 2(xy+yz+xz)
20- 16t(5-t)
Step-by-step explanation:
19) factor 2xy+2yz+2xz
2xy+2yz+2xz
=2(xy+yz+xz)
20) factor -16t^2 +80t
=80t-16t^2
=16(5t-t^2)
=16t(5-t)
