I need help on these few questions. I don't really need the answer I just need to be reminded how to do them and I couldn't find it in my class notes.
A sidewalk of uniform width is built on the inside on all sides of a rectangular grass plot measuring 30m by 40m. The resulting grassy area is then only half the original. How wide is the sidewalk?
A of sidewalk will be= 600m
4x(squared)-152x+840=0 divide by 4
after that I'm stuck
2. Use the discriminant to determine the nature of the roots.
unsure of what I'm to do
3. If 3x(squared)+kx+2x+k-1=0 is to have two equal roots, then k=?
Don't know what to do on this question either thanks for your help I just want to know how to do them and if the one I tried is even right.