Final answer:
The question appears to ask for solving for x but provides conflicting information that does not clearly align with either a geometry or algebra problem. Without additional clarification, a solution cannot be calculated, but if the intent was to solve a quadratic equation, the quadratic formula could be used with the correct values of a, b, and c.
Step-by-step explanation:
The question seems to be asking to solve for x in a geometric context, mentioning points A, B, C, and D, which suggests a problem involving a polygon, possibly a quadrilateral. However, the provided data and expressions seem to be a mix-up with those required for solving a quadratic equation. According to the provided reference, a quadratic equation is in the form at² + bt + c = 0. If we were to apply the quadratic formula, it would be with constants a = 4.90, b (which could be either 14.3 or -14.3, as conflicting values are given), and c = -20.0. However, the actual expressions given in the problem (8x+30 and 4x+18) suggest a different approach, potentially involving linear equations or properties of figures, but not enough information is provided for a complete solution.
Provided we had the correct set of expressions that constitute a quadratic equation, the procedure to solve for x would involve substituting the values of a, b, and c into the quadratic formula and simplifying to find the values of x. For instance, if the quadratic equation were x² + 0.0211x - 0.0211 = 0, we could use the provided solution approach to solve for x, resulting in specific numerical solutions.