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Recap. To determine the equation of a straight line given a gradient ( m ) and y-intercept ( c ). Write the general equation: y = m x + c Substitute the m and c given into the general equation. Simplify equation, where possible. NOTE:.
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Recap To determine the equation of a straight line given a gradient (m) and y-intercept (c). • Write the general equation: y = mx + c • Substitute the m and c given into the general equation. • Simplify equation, where possible.
NOTE: • The 2 main components you need to determine the equation of a straight line are and m c
Now.. What if you were given gradient but No y-intercept • How would you find the equation of the line??? • Well today’s class will focus on finding the equation of a line given: • The gradient (m) and a point on the line. • Two points on the line.
Equation of a line given gradient (m) and a point on the line (x,y) • Label the coordinate given (x, y). • Substitute the value for m, x and y into the equation of a straight line y = mx + c. • Solve the equation to determine the value of c. • To write the equation of the line, substitute the value for m and c into the equation y = mx + c.
Determine the equation of a straight line given that its gradient, m= 3 and it passes through the point (-2, 4).
Equation of a line given 2 points on the line • Label the first coordinate (x1, y1). • Label the second coordinate (x2, y2). • Calculate the gradient (m) of the straight line using the 2 points (x1, y1) and (x2, y2). • Substitute the gradient (m) and one of the coordinates, either (x1, y1) or (x2, y2), into the equation y = mx + c. • Solve the equation to determine the value of c. • To write the equation of the line, substitute the value for m and c into the equation y = mx + c.
Determine the equation of a line that passes through the points (5, 6) and (3, 12).
Final Evaluation • Determine the equation of a straight line given that the gradient is 4 and it passes through the point (-1, 2). • Determine the equation of a straight line given that it passes through the points (5, 4) and (12, -3).