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Find the sum . 2n 3 + 4n 2 - 7 and -n 3 - 8n - 2

2n 3 + 4n 2 - 7 and -n 3 - 8n - 2

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William S. | Experienced scientist, mathematician and instructor - WilliamExperienced scientist, mathematician and...
4.4 4.4 (10 lesson ratings) (10)
1
Robin, I am interpreting this as
 
2*n3 + 4*n2 - 7 + (-n3 - 8*n -2) = n3 + 4n2 - 8n - 9
Vivian L. | Microsoft Word/Excel/Outlook, essay composition, math; I LOVE TO TEACHMicrosoft Word/Excel/Outlook, essay comp...
3.0 3.0 (1 lesson ratings) (1)
0
Hi Robin;
2n3 + 4n2 - 7 and -n3 - 8n - 2
(2n3+4n2-7)+(-n3-8n-2)
Let's combine like terms...
(2n3+-n3)+(4n2)+(-8n)+(-7-2)
 
Addition of a negative number is the same as subtraction of a positive number...
(2n3+-n3)=(2n3-n3)
+(-8n)=-8n
+(-7-2)=-(7+2)
When combining two negative numbers, add the values together and apply a negative sign...
+(-7-2)=-(7+2)=-9
 
n3+4n2-8n-9