Which of the following equations represents a line that passes through the points (8,−2) and (4,3) ?I. y=−45x+10II. 5x+4y=32NeitherI onlyII onlyI and II
Q. Which of the following equations represents a line that passes through the points (8,−2) and (4,3) ?I. y=−45x+10II. 5x+4y=32NeitherI onlyII onlyI and II
Calculate slope between two points: Calculate the slope of the line passing through the points (8,−2) and (4,3). The slope (m) is given by the formula m=(x2−x1)(y2−y1). Using the points (8,−2)(x1,y1) and (4,3)(x2,y2), we get: m=(4−8)(3−(−2))m=(4−8)(3+2)(4,3)0(4,3)1
Check slope in equation I: Check if equation I, y=−45x+10, has the correct slope.The slope of equation I is −45, which matches the slope we calculated in Step 1.
Substitute point into equation I: Substitute one of the points into equation I to see if it satisfies the equation.Let's use the point (8,−2).y=−45x+10−2=−45(8)+10−2=−10+10−2=0This is not true, so equation I does not pass through the point (8,−2).
Write line equation using slope: Write the general form of the line equation using the slope and one of the points.Using the point-slope formy−y1=m(x−x1), with m=−45 and point (8,−2), we get:y−(−2)=−45(x−8)y+2=−45x+10y=−45x+10−2y=−45x+8This is the equation of the line in slope-intercept form.
Check equation II for same line: Check if equation II, 5x+4y=32, represents the same line.We can convert equation II to slope-intercept form to compare the slopes and y-intercepts.5x+4y=324y=−5x+32y=−45x+8This matches the equation we derived in Step 4, so equation II has both the correct slope and y-intercept.
Verify equation II with point (8,−2): Verify that equation II passes through both points by substituting them into the equation.First, use the point (8,−2):5(8)+4(−2)=3240−8=3232=32This is true, so the point (8,−2) lies on the line represented by equation II.
Verify equation II with point (4,3): Now, use the point (4,3) to verify equation II:5(4)+4(3)=3220+12=3232=32This is true, so the point (4,3) also lies on the line represented by equation II.
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