## College Algebra (10th Edition)

The 5th term is $\binom{7}{4}3^4x^3=2835x^3$
By using the binomial theorem we can expand the algebraic expression in the form of: $(x+b)^n=\binom{n}{0}b^0x^n+\binom{n}{1}ab^1x^{n-1}+...+\binom{n}{n-i}b^{n-i}x^{i}+...+\binom{n}{n-1}b^{n-1}x^1+\binom{n}{n}b^nx^0$ We expand the given expression: $(x+3)^7=\binom{7}{0}3^0x^7+\binom{7}{1}3^1x^6+\binom{7}{2}3^2x^5+\binom{7}{3}3^3x^4+\binom{7}{4}3^4x^3+\binom{7}{5}3^5x^2+\binom{7}{6}3^6x^1+\binom{7}{7}3^7x^0$ The 5th term is $\binom{7}{4}3^4x^3=2835x^3$