Answer:
$82.5
Step-by-step explanation:
$16.50 * 5 = $82.5
3/7 = 9/x
cross multiply because thats how u solve proportions
(3)(x) = (7)(9)
3x = 63
x = 63/3
x = 21
and if u will notice : 3/7 and 9/21 ....9/21 reduces to 3/7....so these are equivalent fractions...because proportions are nothing but equivalent fractions
Do 72 divided by 7 to get your answer
27x^2-81x-9x+27 In this case, just in your mind multiply 27 (coefficient of x^2) by the constant value 27(the end value of the quadratic trinomial). Then find factors that give you the value -90 when you add and 729 (27*27) when you multiply.
Factorise the values
27x( x-3)-9(x-3)
Which will give you
(27x-9)(x-3)