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# Which of the following equations is not a correct use of the distributive property to simplify computation?

A. -3 (19) = -3(20) -3 (-1)

B.-3 (19) = (-3)(20) +(-3)(1)

C.-3 (19) = (-3)(20) + (-3) (-1)

D. -3 (19) = (-3)(10) + (-3) (9)

### 2 Answers by Expert Tutors

Arthur D. | Effective Mathematics TutorEffective Mathematics Tutor
5.0 5.0 (9 lesson ratings) (9)
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19=20 +(-1) or 19=10+9
19 does NOT equal 20+1
therefore B is not a correct use of the distributive property
Felice R. | Need Help in Math and Science - Engineer willing to helpNeed Help in Math and Science - Engineer...
4.0 4.0 (1 lesson ratings) (1)
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Marion,

if you remember the distributive property is easy to remember if you think

which can be written as

a(b+c) = ab + ac

If you take your all your equations it looks like you are trying to show distributive property using -3(19)

well in this case our a is  -3

but we don't have our or c

or do we

in A. you have the eqn -3(10) = -3(20) - 3(-1)

if we assume that 20  is b and -1 is c
then we would have -3(20 + (-1)) = -3(20) - 3(-1) and (20+(-1)) = 19

so A would be a correct usage of the distributive property

in B. you have (-3)(20) + (-3)(1) = -3(20+1)  but 20 + 1 ≠ 19
so it wouldn't be a correct usage of the  distributive property

for C and D you would need to do the same as I did above

Hope this helps

F

BTW you can find more examples for this property and others at Purple Math