its a quadratic so to find where it crosses x axis, y=0. we know that one part of the quadratic is x-6 because it crosses x axis at x=6 from the graph. also on the graph it shows it crosses the x axis when x=0. therefore instead of a normal quadratic like for example (x-6)(x-3)=0 its going to be x(x-6)=0(y is 0 when quadratic crosses x axis). However, it could also be 100x(x-6)=0 because then the solutions will still be x-6=0, x=6 and 100x=0, x =0. So we know that it can be any multiple of x, not strictly just a single 'x'. so to find what what the multiple 'a' of x is, we know that two coordinates on the quadratic are 10,80 so just plug it in to the equation: 80=a(10)(10-6) so 80=40a and a =2. Hopefully that makes sense.
thank you so much for this video you legend, your soft spoken voice is very soothing for maths. keep it up!! 🙏🙏🔥🔥
i do not undestad why in question 8 it is ax. Shouldnt it just be x since we know x=o
its a quadratic so to find where it crosses x axis, y=0. we know that one part of the quadratic is x-6 because it crosses x axis at x=6 from the graph. also on the graph it shows it crosses the x axis when x=0. therefore instead of a normal quadratic like for example (x-6)(x-3)=0 its going to be x(x-6)=0(y is 0 when quadratic crosses x axis). However, it could also be 100x(x-6)=0 because then the solutions will still be x-6=0, x=6 and 100x=0, x =0. So we know that it can be any multiple of x, not strictly just a single 'x'. so to find what what the multiple 'a' of x is, we know that two coordinates on the quadratic are 10,80 so just plug it in to the equation: 80=a(10)(10-6) so 80=40a and a =2. Hopefully that makes sense.