Take half of the coefficient of x (which is 2/5) and square it:
[ (1/2)(2/5) ]^2 = (1/5)^2 = 1/25, or 0.04
Thus, to rewrite x^2 + (2/5)x to include a perfect square trinomial,
x^2 + (2/5)x = x^2 + (2/5)x + (1/5)^2 - (1/5)^2, or
(x+1/5)^2 - (1/5)^2, or (x + 1/5)^2 - 1/25
Answer:
the value of x is acb 133°
