To solve the given problem, we need to evaluate each algebraic expression by substituting the given values for the variables. Let's go through each expression step by step.
Expression 1: $-4 - 8f$, if $f = -6$
\[
-4 - 8f = -4 - 8(-6)
\]
First, calculate $-8 \times -6$:
\[
-8 \times -6 = 48
\]
Now substitute back:
\[
-4 + 48 = 44
\]
So, the value is:
\[
\boxed{44}
\]
Expression 2: $7n - 2$, if $n = -8$
\[
7n - 2 = 7(-8) - 2
\]
First, calculate $7 \times -8$:
\[
7 \times -8 = -56
\]
Now substitute back:
\[
-56 - 2 = -58
\]
So, the value is:
\[
\boxed{-58}
\]
Expression 3: $-4 + 4r$, if $r = -5$
\[
-4 + 4r = -4 + 4(-5)
\]
First, calculate $4 \times -5$:
\[
4 \times -5 = -20
\]
Now substitute back:
\[
-4 - 20 = -24
\]
So, the value is:
\[
\boxed{-24}
\]
Expression 4: $-4r + 9$, if $r = 3$
\[
-4r + 9 = -4(3) + 9
\]
First, calculate $-4 \times 3$:
\[
-4 \times 3 = -12
\]
Now substitute back:
\[
-12 + 9 = -3
\]
So, the value is:
\[
\boxed{-3}
\]
Expression 5: $8 + 3z$, if $z = -2$
\[
8 + 3z = 8 + 3(-2)
\]
First, calculate $3 \times -2$:
\[
3 \times -2 = -6
\]
Now substitute back:
\[
8 - 6 = 2
\]
So, the value is:
\[
\boxed{2}
\]
Expression 6: $\frac{15}{d} - 2$, if $d = -5$
\[
\frac{15}{d} - 2 = \frac{15}{-5} - 2
\]
First, calculate $\frac{15}{-5}$:
\[
\frac{15}{-5} = -3
\]
Now substitute back:
\[
-3 - 2 = -5
\]
So, the value is:
\[
\boxed{-5}
\]
Expression 7: $-8c + 6$, if $c = 3$
\[
-8c + 6 = -8(3) + 6
\]
First, calculate $-8 \times 3$:
\[
-8 \times 3 = -24
\]
Now substitute back:
\[
-24 + 6 = -18
\]
So, the value is:
\[
\boxed{-18}
\]
Expression 8: $-7 + 3s$, if $s = -4$
\[
-7 + 3s = -7 + 3(-4)
\]
First, calculate $3 \times -4$:
\[
3 \times -4 = -12
\]
Now substitute back:
\[
-7 - 12 = -19
\]
So, the value is:
\[
\boxed{-19}
\]
Expression 9: $9 - 2h$, if $h = -4$
\[
9 - 2h = 9 - 2(-4)
\]
First, calculate $-2 \times -4$:
\[
-2 \times -4 = 8
\]
Now substitute back:
\[
9 + 8 = 17
\]
So, the value is:
\[
\boxed{17}
\]
Expression 10: $19 - \frac{21}{h}$, if $h = -3$
\[
19 - \frac{21}{h} = 19 - \frac{21}{-3}
\]
First, calculate $\frac{21}{-3}$:
\[
\frac{21}{-3} = -7
\]
Now substitute back:
\[
19 - (-7) = 19 + 7 = 26
\]
So, the value is:
\[
\boxed{26}
\]
Final Answer:
\[
\boxed{44, -58, -24, -3, 2, -5, -18, -19, 17, 26}
\]
Parent Tip: Review the logic above to help your child master the concept of algebraic expressions 7th grade.
