a) Factorise: 2x^2-72, and hence b) find the y-intercept of the line with the equation: y=(2x^2-72)/(4x-24)

a) Take out the common factor, giving: 2(x²-36), idenitfy the difference of two squares and factoise accordingly, giving: 2(x-6)(x+6)
b) you have the facotirse version of the top of the fraction from part a), factorise the bottom, giving: 4(x-6), then cancel and simplify, giving: y=1/2x+3
Then let x=0 to find the y-intercept to be when y=3