What is the sum of all the coefficients in $(1+x)7$ binomial expansion?

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Answer 1 · 2017-08-05T16:24:12

$2^7=128.$

Knowing that, the Expansion of $(1+x)^7,$ is a poly. of degree $7,$

suppose that,

$(1+x)^7=a_0+a_1x+a_2x^2+...+a_7x^7....(star).$

Note : We can actually expand $(1+x)^7,$ but we don't need that.

$:. x=1,$

$rArr 2^7=a_0+a_1+a_2+...+a_7"=the desired sum of the co-effs."$

What is the sum of all the coefficients in (1+x)7 (1+x)7 binomial expansion?