Solve for x and find an approximate value $15 =  \dfrac{((x+3)+(2x-3))h}{2}$
h = $(2x-3) -(x+3) $
& it is also given that $\sqrt{19}$ = 4.36
How can I simplify this & can you help me by explaining the steps

$$30 = ((2x-3)+(x+3))((2x-3)-(x+3))=(2x-3)^2-(x+3)^2=3x^2-18x$$
$$x^2-6x=10$$
$$x^2-6x+9=19$$
$$x=3\pm\sqrt {19}$$
