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QProblem

why did you divide by 2 first?

ASolution

When we solve a quadratic, we can first simplify the equation by dividing every term by the same non‑zero number.
In the problem

2x28x+6=02x^{2}-8x+6=0

the coefficient of x2x^{2} is 22. Dividing the whole equation by 22 gives a simpler, “monic’’ quadratic (one whose leading coefficient is 1):

2x228x2+62=0x24x+3=0.\frac{2x^{2}}{2}-\frac{8x}{2}+\frac{6}{2}=0\quad\Longrightarrow\quad x^{2}-4x+3=0 .

Why do this?

  1. Easier arithmetic – Smaller numbers mean fewer chances for arithmetic errors.

  2. Factoring becomes straightforward – With a leading coefficient of 1, we look for two numbers that multiply to cc (here 3) and add to bb (here –4). Those numbers are 1-1 and 3-3, so

    x24x+3=(x1)(x3)=0.x^{2}-4x+3=(x-1)(x-3)=0 .
  3. The quadratic formula works either way, but the discriminant calculation is simpler when the coefficients are smaller.

If you prefer to keep the original coefficients, you can still apply the quadratic formula directly:

x=b±b24ac2a=(8)±(8)24(2)(6)2(2)=8±44,x=\frac{-b\pm\sqrt{b^{2}-4ac}}{2a} =\frac{-(-8)\pm\sqrt{(-8)^{2}-4(2)(6)}}{2(2)} =\frac{8\pm4}{4},

which leads to the same roots x=1x=1 and x=3x=3.

So dividing by 2 first is just a convenient shortcut; it doesn’t change the solutions, it only makes the algebra a bit cleaner.


If you’d like to see a visual comparison of solving the quadratic with and without that initial division, the video below walks through both approaches.

Shared on 8/20/2026

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