What is the equation in slope-intercept form of the linear function represented by the table?
x
y
–6
–18
–1
–8
4
2
9
12
y = negative 2 x minus 6
y = negative 2 x + 6
y = 2 x minus 6
y = 2 x + 6
y = -2x + 6
What is the equation of the line passing through the points (2, –1) and (5, –10) in slope-intercept form?
y = negative 3 x minus 5
y = negative 3 x + 5
y = 3 x minus 5
y = 3 x + 5
y = -3x + 5
Brooke found the equation of the line passing through the points (–7, 25) and (–4, 13) in slope-intercept form as follows.
Step 1: m = StartFraction 13 minus 25 Over negative 4 minus (negative 7) EndFraction = StartFraction negative 12 Over 3 EndFraction = negative 4. Step 2: y = negative 4 x + b. 25 = negative 4 (negative 7) + b. 25 = 28 + b. 25 minus 28 = 28 + b minus 28. b = negative 3. Step 3: y = negative 3 x minus 4
The equation of the line passing through the points (–7, 25) and (–4, 13) is y = -3x - 4 (Brooke made an error in step 3 by writing -4 instead of -3.)
Brooke found the equation of the line passing through the points (–7, 25) and (–4, 13) in slope-intercept form as follows.
Step 1: m = StartFraction 13 minus 25 Over negative 4 minus (negative 7) EndFraction = StartFraction negative 12 Over 3 EndFraction = negative 4. Step 2: y = negative 4 x + b. 25 = negative 4 (negative 7) + b. 25 = 28 + b. 25 minus 28 = 28 + b minus 28. b = negative 3. Step 3: y = negative 3 x minus 4
What was Brooke’s error?
She found the incorrect slope in step 1.
She mixed up the x- and y-coordinates when she plugged in the point in step 2.
She found the incorrect y-intercept in step 2.
She mixed up the slope and y-intercept when she wrote the equation in step 3.
She found the incorrect y-intercept in step 2.
Which line has an equation of y = negative 5 x + 4 in slope-intercept form?
a line passing through the points (1, 9) and (3, 19)
a line passing through the points (2, –14) and (4, –24)
a line passing through the points (1, 1) and (3, 11)
a line passing through the points (2, –6) and (4, –16)
a line passing through the points (2, –14) and (4, –24)
What method can be used to write the equation of a line in slope-intercept form given two points?
Find the slope using the formula m = StartFraction y 2 minus y 1 Over x 2 minus x 1 EndFraction, and then substitute one point and the slope into the equation y = m x + b to find the y-intercept.
Find the slope using the formula m = StartFraction x 2 minus x 1 Over y 2 minus y 1 EndFraction, and then substitute one point and the slope into the equation y = m x + b to find the y-intercept.
Find the y-intercept using the formula m = StartFraction y 2 minus y 1 Over x 2 minus x 1 EndFraction, and then substitute one point and the y-intercept into the equation y = m x + b to find the slope.
Find the y-intercept using the formula m = StartFraction x 2 minus x 1 Over y 2 minus y 1 EndFraction, and then substitute one point and the y-intercept into the equation y = m x + b to find the slope.