Assignment The sum of the digits of a two-digit
number is to. The result of subtracting
twice the units digit from three times
the tens digit is 15. find the number.

the correct answer is

lets say the number xy (x in tens place and y in units place)

first equation (x+y =10 i.e x=10-y

also 3x-2y=15 i.e 2y=3x-15)

second equation

substitution the value of x from first equation in second equation (or you can do vice- versa)gives you 2y=3(10-y)-15 and so,

2y=30-3y-15 i.e5y=15 and y=3

since x=10-y; x=10-3 which is 7

the answer is 73.

Step-by-step explanation:

hope this helps you

hello from mrbilldoesmath!

answer:

25x^2 + 90x + 84

discussion:

mn(x) = m(n(x)) = m( 5x + 9) =

(5x + 9)^2 + 3 =>

25x^2 + 90x + 9^2 + 3 =

25x^2 + 90x + 84                 (as 9^2 = 9*9 = 81)

which is the second choice

regards,  

mrb

p.s.   i'll be on vacation from friday, dec 22 to jan 2, 2019. have a great new year!