What tool can you use to find solutions to equations such as 2x^2 - 13x + 18?

What tool can you use to find solutions to equations such as 2x^2 - 13x + 18?

• A. Graphing Calculator
• B. Ruler
• C. Protractor
• D. Compass

Answer: (A)

Graphing a quadratic to find its solutions works because the points where the graph crosses the x-axis are the x-values that make the equation true. For 2x^2 - 13x + 18, plotting y = 2x^2 - 13x + 18 shows the zeros at x = 2 and x = 9/2. You can also factor to get (2x - 9)(x - 2), yielding the same roots. A graphing calculator is a handy tool here because you can enter the quadratic and use the graph or a zero/root function to get the x-intercepts quickly. In contrast, a ruler, protractor, or compass are for measuring lengths and angles and don’t help you compute algebraic solutions.

Graphing a quadratic to find its solutions works because the points where the graph crosses the x-axis are the x-values that make the equation true. For 2x^2 - 13x + 18, plotting y = 2x^2 - 13x + 18 shows the zeros at x = 2 and x = 9/2. You can also factor to get (2x - 9)(x - 2), yielding the same roots. A graphing calculator is a handy tool here because you can enter the quadratic and use the graph or a zero/root function to get the x-intercepts quickly. In contrast, a ruler, protractor, or compass are for measuring lengths and angles and don’t help you compute algebraic solutions.