FIND THE INTERCEPTS OF THE LINE 3X 4Y 24.
• X-INTERCEPT: THE X-COORDINATE OF THE POINT AT WHICH A LINE CROSSES THE X-AXIS
• Y-INTERCEPT: THE Y-COORDINATE OF THE POINT AT WHICH A LINE CROSSES THE Y-AXIS
• YOU CAN FIND THE INTERCEPTS OF A LINE FROM ITS EQUATION.
• THEN YOU CAN USE THE INTERCEPTS TO GRAPH THE LINE.
• FOR THE X-INTERCEPT LET Y BE 0
• 3X 4Y 24
• 3X+4(0)=24
• 3X=24
•=• X=8
• (8,0)
• FOR THE Y-INTERCEPT LET X BE 0
• 3X 4Y 24
• 3(0)+4Y=24
• 4Y=24
•=• Y=6
• (0,6)
TWO OTHER FORMS OF EQUATIONS• STANDARD FORM
• AX+BY=C
• A AND B ARE BOTH WHOLE NUMBERS
• X AND Y ARE BOTH ON SAME SIDE OF EQUATION
• POINT SLOPE FORM
• (Y1-Y2)=M(X1-X2)
• THE TWO POINTS ARE (X,Y) AND (X,Y)
WHY DO WE NEED ALL THREE
• WE CAN USE ONE TYPE OF EQUATION TO GET TO OTHER TYPE
• DEPENDING ON INFORMATION GIVEN WE CAN CREATE ONE TYPE AND CONVERT TO ANOTHER
SOME EXAMPLES• IF GIVEN TWO POINTS (1,2)(3,4)
• YOU CAN CREATE POINT SLOPE FORM
• SLOPE ===1
• SO (Y-Y)=M(X-X)
• (4-2)=1(3-1)
GO TO STANDARD FORM• IF GIVEN TWO POINTS (1,2)(3,4)
• SLOPE ===1
• CHOOSE ONE POINT TO USE
• (Y-4)=1(X-3)
• DISTRIBUTE
• (Y-4)=(X-3)
• ADD 4 TO BOTH SIDES
• Y=X+1, NOW YOU ARE IN SLOPE INTERCEPT FORM
YOU CAN CONVERT BETWEEN ALL THREE
• YOU CAN FIND SLOPE WITH ALL THREE
• YOU CAN FIND Y AND X INTERCEPTS IN ALL FORMS
• YOU CAN GRAPH FROM ALL THREE FORMS