Question

.Subtract (7a-2b+3c) from the sum of (4a+3b+9c) and(-a-7b-3c).​

Answer 1

Step-by-step explanation:

It is instructed to subtract (2a−3b+4c)from the sum of (a+3b−4c),(4a−b+9c) and (−2b+3c−a).

So, First we will do the sum of the three given polynomials,

Sum =(a+3b−4c)+(4a−b+9c)+(−2b+3c−a)

=(a+4a−a)+(3b−b−2b)+(−4c+9c+3c)

=4a+8c

Now, we can perform the subtraction,

∴  Required difference

=(4a+8c)−(2a−3b+4c)

=4a+8c−2a+3b−4c

=2a+3b+4c

Answer 2

Step-by-step explanation:

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Sum = 4a+3b+9c+(-a)-7b-3c

= 4a+(-a)+3b-7b+9c-3c

= 3a-4b+6c

Sub = 7a-2b+3c-(3a-4b+6c)

= 7a-2b+3c-3a+4b-6c

= 7a-3a-2b+4b+3c-6c

= 4a+2b-3c