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 9th Grader, from Kansas
find the value of c that makes the expression a perfect square trinomial, then write the expression as the square of a binomial: x^2=4/7x+c
The answer for your question x^2 + 4x/7 +c , c= (2/7)^2 = 4/49, than expression will be x^2 + 4x/7 + (2/7)^2 = (x+2/7)^2