McGraw Hill Glencoe Algebra 2, 2012
MH
McGraw Hill Glencoe Algebra 2, 2012 View details
Mid-Chapter Quiz
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Exercise 22 Page 91

Start by using the Slope Formula to find the slope.

y=-1/3x+7/3

Practice makes perfect

An equation in slope-intercept form follows a specific format. y= mx+b For an equation in this form, m is the slope and b is the y-intercept. Let's use the given points to calculate m. We will start by substituting the points into the Slope Formula. m = y_2-y_1/x_2-x_1 Note that it does not matter which point we choose to use for ( x_1, y_1) and ( x_2, y_2), since the result of using the Slope Formula will be the same.

m=y_2- y_1/x_2- x_1
m=1- 3/4-( - 2)
â–¼
Simplify right-hand side
m=1-3/4+2
m=- 2/6
m=- 1/3
m= -1/3

A slope of - 13 means that for every 3 horizontal step in the positive direction, we take 1 vertical steps in the negative direction. Now that we know the slope, we can write a partial version of the equation. y= -1/3 x+b To complete the equation, we also need to determine the y-intercept, b. Since we know that the given points will satisfy the equation, we can substitute one of them into the equation to solve for b. Let's use ( - 2, 3).

y=-1/3x+b
3=-1/3( - 2)+b
â–¼
Solve for b
3=-1(- 2)/3+b
3=-- 2/3+b
3=2/3+b
3-2/3=b
3* 3/3-2/3=b
9/3-2/3=b
7/3=b
b=7/3

A y-intercept of 73 means that the line crosses the y-axis at the point (0,73). We can now complete the equation. y= -1/3x+7/3