Top one would make more sense
Answer:
Part a)
of fabric
Part b)
of thread
Step-by-step explanation:
we know that
A seamstress uses
centimeters of thread for every
centimeters of fabric
Part a)
by proportion
Find how much fabric is involved if the seamstress uses
centimeters of thread
![\frac{7.6}{5.7}\frac{cm\ fabric}{cm\ thread} =\frac{x}{4.2}\frac{cm\ fabric}{cm\ thread} \\ \\x=4.2*7.6/5.7\\ \\x=5.6\ cm\ fabric](https://tex.z-dn.net/?f=%5Cfrac%7B7.6%7D%7B5.7%7D%5Cfrac%7Bcm%5C%20fabric%7D%7Bcm%5C%20thread%7D%20%3D%5Cfrac%7Bx%7D%7B4.2%7D%5Cfrac%7Bcm%5C%20fabric%7D%7Bcm%5C%20thread%7D%20%5C%5C%20%5C%5Cx%3D4.2%2A7.6%2F5.7%5C%5C%20%5C%5Cx%3D5.6%5C%20cm%5C%20fabric)
Part b)
by proportion
Find how many centimeters of thread is needed if the seamstress is working with
centimeters of fabric
![\frac{7.6}{5.7}\frac{cm\ fabric}{cm\ thread} =\frac{21.2}{x}\frac{cm\ fabric}{cm\ thread} \\ \\x=5.7*21.2/7.6\\ \\x=15.9\ cm\ thread](https://tex.z-dn.net/?f=%5Cfrac%7B7.6%7D%7B5.7%7D%5Cfrac%7Bcm%5C%20fabric%7D%7Bcm%5C%20thread%7D%20%3D%5Cfrac%7B21.2%7D%7Bx%7D%5Cfrac%7Bcm%5C%20fabric%7D%7Bcm%5C%20thread%7D%20%5C%5C%20%5C%5Cx%3D5.7%2A21.2%2F7.6%5C%5C%20%5C%5Cx%3D15.9%5C%20cm%5C%20thread)
Answer:
9. ![\\-(2b-7a)(b+a)](https://tex.z-dn.net/?f=%5C%5C-%282b-7a%29%28b%2Ba%29)
10. ![mn(m^{2}-3mn+8n^{2} )](https://tex.z-dn.net/?f=mn%28m%5E%7B2%7D-3mn%2B8n%5E%7B2%7D%20%29)
Step-by-step explanation:
9. ![-2b^{2} +5ab+7a^{2}\\](https://tex.z-dn.net/?f=-2b%5E%7B2%7D%20%2B5ab%2B7a%5E%7B2%7D%5C%5C)
Write 5ab as a difference.
![-2b^{2} -2ab+7ab+7a^{2}\\](https://tex.z-dn.net/?f=-2b%5E%7B2%7D%20-2ab%2B7ab%2B7a%5E%7B2%7D%5C%5C)
Factor out the greatest common factor (GCFs).
![-2b(b+a)+7a(b+a)\\\\-(2b-7a)(b+a)](https://tex.z-dn.net/?f=-2b%28b%2Ba%29%2B7a%28b%2Ba%29%5C%5C%5C%5C-%282b-7a%29%28b%2Ba%29)
10. ![-3m^{2} n^{2} +8mn^{3}+m^{3}n](https://tex.z-dn.net/?f=-3m%5E%7B2%7D%20n%5E%7B2%7D%20%2B8mn%5E%7B3%7D%2Bm%5E%7B3%7Dn)
Factor out the GCF which would be mn.
Rewrite.
![mn(m^{2}-3mn+8n^{2} )](https://tex.z-dn.net/?f=mn%28m%5E%7B2%7D-3mn%2B8n%5E%7B2%7D%20%29)