Thuy planned for a square table to have a side length of 30 in. but found that it could be a little bigger at 39 in. She found the change of scale below. StartFraction 39 inches divided by 3 over 30 inches divided by 3 EndFraction = StartFraction 13 over 10 EndFraction. The change of scale is 13 to 10. What is Thuy’s error? Thuy should have written the ratio as StartFraction 30 inches over 3 inches EndFraction. Thuy should have written the ratio as StartFraction 30 inches over 39 inches EndFraction. Thuy should have divided both numbers by 6. Thuy should have divided both numbers by 13.

Step-by-step explanation:

Thuy planned for a square table to have a side length of 30 in. but found that it could be a little bigger at 39 in. She found the change of scale below. StartFraction 39 inches divided by 3 over 30 inches divided by 3 EndFraction = StartFraction 13 over 10 EndFraction. The change of scale is 13 to 10.

Thuy should have written the ratios as 30in/39in. - is Thuy error

Step-by-step explanation:

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!

3

step-by-step explanation:

divide 13.5 by 9 to get the scale factor. it equals 1.5

2 * 1.5 = 3