Select the correct values. Identify each x-value at which the slope of the tangent line to the function f(x) = 0.2x~ + 5x - 12 belongs to the interval (-1, 1). f ( x ) = x' +4x -21 x- - 8x + 15 i( x) = x- -13x + 42 X - 5 2x2 - 5x + 12 X+4 g(x) = i( x) 2x +3 -2x + 8 2x- + x-15 h(X)= X - 3 k(x) = x2 -9 2x - 5