At the factory a baseball card is places in every 9th cereal package a football card is placed in every 25th package what is the first package that gets both the baseball and football card

[10 points, algebra 2]according to my answer key the restrictions are -1 and 4. but why not positive 1?

Data from 2005 for various age groups show that for each $100 increase in the median weekly income for whites, the median weekly income of blacks increases by $105. also, for workers of ages 25 to 54 the median weekly income for whites was $676 and for blacks was $527. (a) let w represent the median weekly income for whites and b the median weekly income for blacks, and write the equation of the line that gives b as a linear function of w. b = (b) when the median weekly income for whites is $760, what does the equation in (a) predict for the median weekly income for blacks?

What is the simplified form of square root of 400 to the 100th power ?