Question

Shawna, Dexter, and Tilana are solving the equation mc010-1.jpg. Shawna says, “I can begin by dividing each side of the equation by –2.5 to get mc010-2.jpg.” Dexter says, “I can begin by distributing mc010-3.jpg to get mc010-4.jpg.” Tilana says, “I can begin by multiplying each side of the equation by mc010-5.jpg to get mc010-6.jpg.” Which students are correct? only Shawna and Tilana only Shawna and Dexter only Dexter and Tilana Shawna, Dexter, and Tilana

Answer 1

Shawna, Dexter, and Tilana are all correct!

Answer 2

Shawna, Dexter, and Tilana are correct.

Explanation:

The equation is:

-2.5(5-n)+2=15

Shawna proposed divide each side of the equation by –2.5 to get:

5-n-2/2.5=-15/2.5

That is correct because if you divide at both sides of an equation the result doesn't change, then she applied the distributive property of division correctly.

Dexter proposed distributing the -2.5 to get:

-12.5+2.5n+2=15

which is also correct because -2.5*5 = -12.5 and -2.5*(-n) = 2.5n

Tilana proposed multiply each side of the equation by -1/2.5 to get:

5-n-0.8=-6

which is also correct because if you multiply at both sides of an equation the result doesn't change, then she applied the distributive property of multiplication correctly. Notice that this is equivalent to Shawna's idea.