Question

-2a + (-3a) =
)、-8z - (-7z) =
) 5x - 7x =
) -3x + 4 - x - 9 =

Explanation:

Step1: Simplify \(-2a + (-3a)\)

When adding like terms, we add the coefficients. The coefficient of \(a\) in \(-2a\) is \(-2\) and in \(-3a\) is \(-3\). So, \(-2 + (-3)=-5\). Thus, \(-2a + (-3a)=-5a\).

Step2: Simplify \(-8z - (-7z)\)

Subtracting a negative is like adding the positive. So, \(-8z - (-7z)=-8z + 7z\). Now, add the coefficients: \(-8 + 7=-1\). Thus, \(-8z - (-7z)=-z\).

Step3: Simplify \(5x - 7x\)

Add the coefficients of \(x\): \(5 - 7=-2\). Thus, \(5x - 7x=-2x\).

Step4: Simplify \(-3x + 4 - x - 9\)

First, combine like terms for \(x\): \(-3x - x=-4x\). Then, combine the constant terms: \(4 - 9=-5\). So, \(-3x + 4 - x - 9=-4x - 5\).

Answer:

\(-2a + (-3a)=\boldsymbol{-5a}\)
\(-8z - (-7z)=\boldsymbol{-z}\)
\(5x - 7x=\boldsymbol{-2x}\)
\(-3x + 4 - x - 9=\boldsymbol{-4x - 5}\)