It is substitution. Because you are substituting 3=y into x+5=3
The answer is FALSE because an inequality that can sometimes be equal or can where one number is greater than or less than a number.
EXAMPLE:
a = a
x > a
a < x
When it's laid out like that. 2 division statements on either side with one unknown variable you just cross multiply really easy
5 x 24 / 6 = 20
Take the number that's on the same position of the x thats 5 then multiply it to the numerator or denominator of the x thats 24 then divide it to its denominator thats 6
The probability could be 1/3 of you rolling a multiple of 3
Use proportions to solve this. Set up the ratios with dollars on the top and pounds on the bottom and then cross-multiply to solve for x. Like this:

. Cross multiplying gives us 800x=168,000. Divide by 800 to get that x = 210. So $300 equals 210 pounds.