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How to Change Binomials Into Slope-Intercept Form

The slope-intercept equation for a line allows you to see at a glance what the line's slope is (i.e., how steeply the line rises or falls) and what its y-intercept is (i.e., where it crosses over the y axis). The basic form of the slope-intercept equation is y = mx + b, where m is the slope of the line and b is the line's y-intercept. A binomial is an algebraic expression with two different terms, such as 7 + 2x, 8 + 3y and 2x + y, and can be converted into slope-intercept form.

Instructions

    • 1

      Check that the binomial can be translated into slope-intercept form. For a binomial to be translatable into slope-intercept form, it must contain either an x or a y term or both, and these terms may only be raised to the first power.

      For example 3 + 15x, 3y + 15 and 3y + 15x are all binomials that can be translated into slope-intercept form because they contains x terms, y terms or both. On the other hand, 3 + 15x^2 cannot be translated into slope-intercept form because its x term is raised to the second power, not the first power.

    • 2

      Set the binomial equal to the term---x or y---that is does not contain. If the binomial contains both x and y, set it equal to 0. However, if you are explicitly told what value the binomial is equal to, such as 3x + y = 5, do not modify the equation.

      For example, for the binomial 3 + 15x, set the equation equal to y because it does not contain y (y = 3 + 15x). For the binomial 3 + 15y, set the equation equal to x because the binomial doesn't contain x (x = 3 + 15y). For the binomial 3x + 15y, which contains both x and y, set the equation equal to 0 (3x + 15y = 0).

    • 3

      Move all y terms to the left side of the equation. To move a term from one side of the equation to the other, subtract it from both sides.

      For example, move the y term in x = 3 + 15y to the left side of the equation by subtracting 15y from both sides. This yields x - 15y = 3 + 15y - 15y, which simplifies to x - 15y = 3, an equation with the y term now on the left side.

    • 4

      Move all x terms to the right side of the equation.

      For x - 15y = 3, move the x term to the right side by subtracting x from both sides of the equation. This yields x - 15y - x = 3 - x, which simplifies to -15y = 3 - x.

    • 5

      Move all numbers not accompanied by an unknown variable, such as x or y, to the right side of the equation and to the right side of the x term.

      For example, in -15y = 3 - x, 3 is the only number not accompanied by the unknown variables x and y. The number 3 is already on the right side of the equation, so simply move it to the right side of the x term by rearranging 3 - x to get -x + 3. This yields -15y = -x + 3.

    • 6

      Divide both sides of the equation by the coefficient preceding the y term. For example, in 3y, 3 is the coefficient preceding the y term. In 10y, 10 is the coefficient preceding the y term.

      In -15y = -x + 3, -15 is the coefficient preceding the y term. Divide both sides of the equation by -15 to obtain (-15y) / -15 = -x/(-15) + 3/(-15), which simplifies to y = x/15 - 3/15. Re-write this as y = (1/15)x - 3/15, because x/15 = (1/15)x.

    • 7

      Simplify the result by reducing any fractions to their simplest form.

      For example, for y = (1/15)x - 3/15, 3/15 can be reduced to 1/5, so the simplified result is y = (1/15)x - 1/5, which is also the end result in slope-intercept form.

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