WordGPT

Solve 4x² + 12x - 7 = 0

The solutions of 4x² + 12x - 7 = 0 are x = 1/2 or x = -7/2.

x² +x += 0
4x2+12x−7=0⇒x=12, −724x^2 + 12x - 7 = 0 \Rightarrow x = \frac{1}{2},\ -\frac{7}{2}
Discriminant D = 256 · x ≈ 0.5, -3.5

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

Explain it step by step in chatMake a short video of it
Graph of y = 4x² + 12x - 7-6-5-4-3-2-1123-20204060x = 0.5x = -3.5vertexy = 4x² + 12x - 7
Graph of y = 4x² + 12x - 7. The curve crosses the x-axis at x = 0.5 and x = -3.5; the vertex is at (-1.5, -16).

How to work it out

  1. 1

    Write it in standard form a x² + b x + c = 0 and read off the coefficients: a = 4, b = 12, c = -7.

    4x2+12x−7=04x^2 + 12x - 7 = 0
  2. 2

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

    D=122−4⋅4⋅(−7)=144+112=256D = 12^2 - 4\cdot4\cdot(-7) = 144 + 112 = 256
  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:

    (2x−1)(2x+7)=0\left(2x - 1\right)\left(2x + 7\right) = 0
  5. 5

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

    2x−1=0⇒x=122x+7=0⇒x=−722x - 1 = 0 \Rightarrow x = \frac{1}{2}\qquad 2x + 7 = 0 \Rightarrow x = -\frac{7}{2}
  6. 6

    Method 2, The quadratic formula works for every quadratic:

    x=−b±D2a=−12±2568x = \frac{-b \pm \sqrt{D}}{2a} = \frac{-12 \pm \sqrt{256}}{8}
  7. 7

    Simplify to get the solutions:

    x=12orx=−72x = \frac{1}{2}\quad\text{or}\quad x = -\frac{7}{2}
  8. 8

    Check by putting x = 1/2 back in: a·x² + b·x + c = 4·(1/4) + 12·(1/2) + (-7) = 0 ✓

LaTeX source of the formulas on this page
\[ 4x^2 + 12x - 7 = 0\ \Rightarrow\ x = \frac{1}{2},\ -\frac{7}{2} \]
\[ 4x^2 + 12x - 7 = 0 \]
\[ D = 12^2 - 4\cdot4\cdot(-7) = 144 + 112 = 256 \]
\[ \left(2x - 1\right)\left(2x + 7\right) = 0 \]
\[ 2x - 1 = 0 \Rightarrow x = \frac{1}{2}\qquad 2x + 7 = 0 \Rightarrow x = -\frac{7}{2} \]
\[ x = \frac{-b \pm \sqrt{D}}{2a} = \frac{-12 \pm \sqrt{256}}{8} \]
\[ x = \frac{1}{2}\quad\text{or}\quad x = -\frac{7}{2} \]

The parabola y = 4x² + 12x - 7

xy
-4.520
-3.50
-2.5-12
-1.5-16
-0.5-12
0.50
1.520

Questions

What are the solutions of 4x² + 12x - 7 = 0?

The solutions of 4x² + 12x - 7 = 0 are x = 1/2 or x = -7/2.

Does 4x² + 12x - 7 = 0 factor?

Yes: (2x-1)(2x+7) = 0.

What is the vertex of y = 4x² + 12x - 7?

(-3/2, -16). The parabola opens upwards, so this is the minimum.

What are the sum and product of the roots?

Sum = −b/a = -3, product = c/a = -7/4.

Similar equations

    Solve 4x² + 12x - 7 = 0: x = 1/2 or x = -7/2 (steps) | WordGPT