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Solve 5x² - 12x + 7 = 0

The solutions of 5x² - 12x + 7 = 0 are x = 7/5 or x = 1.

x² +x += 0
5x2−12x+7=0⇒x=75, 15x^2 - 12x + 7 = 0 \Rightarrow x = \frac{7}{5},\ 1
Discriminant D = 4 · x ≈ 1.4, 1

Change a, b or c (whole numbers, a not 0) and the exact solutions follow.

Graph of y = 5x² - 12x + 7-1123-55101520253035x = 1.4x = 1vertexy = 5x² - 12x + 7
Graph of y = 5x² - 12x + 7. The curve crosses the x-axis at x = 1.4 and x = 1; the vertex is at (1.2, -0.2).

How to work it out

  1. 1

    Write it in standard form a x² + b x + c = 0 and read off the coefficients: a = 5, b = -12, c = 7.

    5x2−12x+7=05x^2 - 12x + 7 = 0
  2. 2

    Work out the discriminant D = b² − 4ac. Its sign tells you how many real solutions there are.

    D=(−12)2−4⋅5⋅7=144−140=4D = (-12)^2 - 4\cdot5\cdot7 = 144 - 140 = 4
  3. 3

    D is positive, so there are two different real solutions.

  4. 4

    Method 1, factoring. The roots are rational, so the left side factors:

    (5x−7)(x−1)=0\left(5x - 7\right)\left(x - 1\right) = 0
  5. 5

    A product is zero when one of its factors is zero, so set each factor equal to 0 and solve:

    5x−7=0⇒x=75x−1=0⇒x=15x - 7 = 0 \Rightarrow x = \frac{7}{5}\qquad x - 1 = 0 \Rightarrow x = 1
  6. 6

    Method 2, The quadratic formula works for every quadratic:

    x=−b±D2a=12±410x = \frac{-b \pm \sqrt{D}}{2a} = \frac{12 \pm \sqrt{4}}{10}
  7. 7

    Simplify to get the solutions:

    x=75orx=1x = \frac{7}{5}\quad\text{or}\quad x = 1
  8. 8

    Check by putting x = 7/5 back in: a·x² + b·x + c = 5·(49/25) + (-12)·(7/5) + 7 = 0 ✓

LaTeX source of the formulas on this page
\[ 5x^2 - 12x + 7 = 0\ \Rightarrow\ x = \frac{7}{5},\ 1 \]
\[ 5x^2 - 12x + 7 = 0 \]
\[ D = (-12)^2 - 4\cdot5\cdot7 = 144 - 140 = 4 \]
\[ \left(5x - 7\right)\left(x - 1\right) = 0 \]
\[ 5x - 7 = 0 \Rightarrow x = \frac{7}{5}\qquad x - 1 = 0 \Rightarrow x = 1 \]
\[ x = \frac{-b \pm \sqrt{D}}{2a} = \frac{12 \pm \sqrt{4}}{10} \]
\[ x = \frac{7}{5}\quad\text{or}\quad x = 1 \]

The parabola y = 5x² - 12x + 7

xy
-1.844.8
-0.819.8
0.24.8
1.2-0.2
2.24.8
3.219.8
4.244.8

Questions

What are the solutions of 5x² - 12x + 7 = 0?

The solutions of 5x² - 12x + 7 = 0 are x = 7/5 or x = 1.

Does 5x² - 12x + 7 = 0 factor?

Yes: (5x-7)(x-1) = 0.

What is the vertex of y = 5x² - 12x + 7?

(6/5, -1/5). The parabola opens upwards, so this is the minimum.

What are the sum and product of the roots?

Sum = −b/a = 12/5, product = c/a = 7/5.

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    Solve 5x² - 12x + 7 = 0: x = 7/5 or x = 1 (steps) | WordGPT