Jakob simplified the expression as shown.
(6.7x-.4x--2)
6.7x-3-3.4x-1-2x-2
(6.7x-3.4x-2x)+(-3-1-2)
1.3x-6
what was jakob's error in subtracting the expressions?
o he used the commutative property incorrectly.
he used the distributive property incorrectly.
o he used the associative property incorrectly.
he simplified the x coefficients incorrectly.

he used the distributive property incorrectly

Step-by-step explanation:

(6.7x-3)-(3.4x-1)-(2x-2)

should equal:

6.7x-3+3.4x+1-2x+2

however jakob put:

6.7x-3-3.4x-1-2x-2

this shows that he distributed the negative sign incorrectly

a

step-by-step explanation:

jjddbdhid r

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!