What is the first step to solving this by substitution? 1 point
y = 2x + 1
y = 4x - 1
O put a zero in for x
O put a zero in for y
O find the slope
O Replace the right side of the top equation with the y on the bottom equation

whaere is the picture

step-by-step explanation:

there is only one way to arrange all the eight relative to each other because they are not distinct. we have

now there are nine places to place an (and not more than one in one place).   because we have four symbols, we need to choose four of these nine places to insert an . order does not matter because the are not distinct.

thus there are 1 · c(9,4) ways, or, if we calculate it,

thus there are 126 ways to form such "words."