How do you work out what the equation of the parallel line to my=2x+3 and passes through (0,7) is?
A line that is parallel has the same gradient. Plug this into y=mx+c (the equation for a straight line) and set y = 7 and x =0 (from the coordinates) in order to find c.
If a line is parallel, then the equation of the parallel line will have the same gradient as the original line. In this case, the gradient of then parallel line will therefore also be 2. So, you start writing y =2x + c. The y intercept however can only be determined by substituting the coordinates into this equation. In this case, x = 0 and y = 7. So you write 7 = (2*0) + c. Therefore c = 7 The equation of the parallel line is therefore y = 2x + 7
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