What is the coefficient of x^2 in (x^3 + x^2 + x + 1)(x^4 + 3x^3 + 8x + 7x + 1)?
What is the coefficient of x^2 in (x^3 + x^2 + x + 1)(x^4 + 3x^3 + 8x + 7x + 1)?
(x3 + x2 + x + 1)(x4 + 3x3 + 8x2 + 7x + 1) I think you left off that exponent.
x2 • 1 = x2
x • 7x = 7x2
1 • 8x2 = 8x2
add them up 16x2
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When we expand the product, we get \(x^7 + 4x^6 + 4x^5 + 19x^4 + 16x^2 + 16x + 1.\) We see that the coefficient of \(x^2\) is \(16\).