A.A.24 Algebraic equation & Inequalities How Braulio, Numan, Monshur, and Willy solved an algebraic...

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Transcript of A.A.24 Algebraic equation & Inequalities How Braulio, Numan, Monshur, and Willy solved an algebraic...

A.A.24 Algebraic equation & Inequalities

How Braulio, Numan, Monshur, and Willy solved an algebraic inequality in their UR

The problem

Solve for X:

Willy: Why do you change the sign from < (is less than) to > (is greater than)?

Braulio: You need to change the sign when you are solving problems with inequality signs.

Willy: But why?

Monshur: Look [point to the text] you don’t change the sign.Numan: You don’t have to change the sign, but I don’t know why

The problem Example from UR

Willy: I learned that you change the sign (inequality) when you divided by a negative number, but here you divided by positive 4, so keep the sign.

Willy’s Ah-Ha Moment!!

Our Take Away

(1) If each side of an inequality is divided by the negative number, then change the sign.

(2) They referenced to an existing example.