Question

How do you add and subtract 3x2+2x−5 and −4+7x2?

Answer 1

Solution:

Let A = 3x²+2x-5,

B = -4+7x²

i) A+B

= 3x²+2x-5

+ 7x²+0x-4

____________

= 10x²+2x-9

____________

ii) A-B

= 3x²+2x-5 - (7x²-4)

= 3x²+2x-5-7x²+4

= 3x²-7x²+2x-5+4

= (3-7)x²+2x-1

= -4x²+2x-1

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