If you already have the equation of the line, you can find the y-intercept with a little algebra.   Example 3: What is the y-intercept of the line x + 4y = 16? Note: Example 3 is a straight line. See the end of this section for an example of a quadratic equation (with a variable raised to the power of 2). The y-axis is a vertical line along x = 0. This means any point on the y-axis has an x-coordinate of 0, including the y-intercept of the line. Plug in 0 for x in the line equation.  Example 3 (cont.): x + 4y = 16x = 00 + 4y = 164y = 16 The answer is the y-intercept of the line.  Example 3 (cont.): 4y = 164y4=164{\displaystyle {\frac {4y}{4}}={\frac {16}{4}}}y = 4.The y-intercept of the line is 4. . To check your answer, graph the equation as neatly as you can. The point where the line crosses the y-axis is the y-intercept. A quadratic equation includes a variable (x or y) raised to the power of 2. You can solve for y with the same substitution, but since the quadratic describes a curve, it could intercept the y-axis at 0, 1, or 2 points. This means you may end up with 0, 1, or 2 answers.  Example 4: To find the y-intercept of y2=x+1{\displaystyle y^{2}=x+1}, substitute x = 0 and solve the quadratic equation.In this case, we can solve y2=0+1{\displaystyle y^{2}=0+1} by taking the square root of both sides. Remember, when taking a square root, you must account for two answers: a negative and a positive.y2=1{\displaystyle {\sqrt {y^{2}}}={\sqrt {1}}}y = 1 or y = -1. These are both y-intercepts of this curve.

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Write a summary of the previous text in Indonesian:
Tuliskan persamaan garis. Ganti x dengan 0. Temukan nilai Y. Uji kebenaran jawaban dengan grafik (opsional) Temukan perpotongan Y untuk persamaan kuadrat.