Question

Simplify 7x2(3x – 9) + 3 and find its values for x = 4 and x = 6. answer must be 2268

Answer 1

Step-by-step explanation:

7x^2(3x-9)+3

=>21x^3+3

For x=4

=>21(4)^3+3

=>21×48+3

=>1006

For x=6

=>21(6)^3+3

=>21×216+3

=>4536+3

=>4539

Answer 2

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7x^2(3x – 9) + 3

Solve for 7x^2(3x – 9)

= (7x^2 × 3x) – (7x^2 × 9) (using distributive law: a(b – c) = ab – ac)

= 21x^3 – 63x^2

So, 7x^2(3x – 9) + 3

= 21x^3 – 63x^2 + 3

Now, for x = 4,

21x^3 – 63x^2 + 3

= 21 × 43 – 63 × 42 + 3

= 1344 – 1008 + 3

= 336 + 3 = 339

Now, for x = 6,

21x^3 – 63x^2

= 21 × 63 – 63 × 62 + 3

= 2268 + 3

= 2271

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Hope it's Helpful.....:)