Question Video: Subtraction of Two Algebraic Expressions | Nagwa Question Video: Subtraction of Two Algebraic Expressions | Nagwa

Question Video: Subtraction of Two Algebraic Expressions Mathematics • 7th Grade

Simplify (𝑡² + 5) − (2𝑡² + 2).

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Video Transcript

Simplify 𝑡 squared plus five minus two 𝑡 squared plus two.

In order to solve this problem, we need to group or collect the like terms. We need to group the 𝑡 squared and the two 𝑡 squared. And we also need to group the positive five and positive two.

Before we collect the like terms, it is worth remembering what happens when two signs are touching.

If we have two positive signs, our resultant sign is also positive or addition. If we have a negative and a positive sign in either order, the resultant will be a negative or subtraction sign. And if we have two negative signs, the resultant sign is positive.

Our first step is to subtract two 𝑡 squared from 𝑡 squared. As 𝑡 squared is the same as one 𝑡 squared, we need to subtract two from one. One minus two is equal to negative one. Therefore, we are left with negative one 𝑡 squared or just negative 𝑡 squared.

Next, we need to group the numbers. We have positive five minus positive two. The negative and positive signs that are touching become a negative. So we are left with positive five minus two. This is equal to three or positive three.

We can therefore say that 𝑡 squared plus five minus two 𝑡 squared plus two is equal to negative 𝑡 squared plus three.

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