We'll use another method to determine the interval of x
values where the given expression is positive.
According to
the rule, between the roots of the expression 4x^2+ 8x + 3, the expression has the
opposite sign of the coefficient of x^2 and outside the roots, the expression has the
same sign as the coefficient of x^2.
We'll calculate the
roots:
4x^2+ 8x + 3 = 0
We'll
apply the quadratic formula:
x1 = [-8 +
sqrt(64-48)]/8
x1 = (-8 +
4)/8
x1 =
-1/2
x2 =
(-8-4)/8
x2 =
-3/2
So, the expression is
positive over the
intervals:
(-inf.,
-3/2)U(-1/2,+inf.)
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