Practice Evaluating Expressions in Two Variables

1. Evaluate ‍$$3 + jk + k^3$$ when $$j = 2$$ and ‍$$k = 6$$.

2. Evaluate ‍$$8r -rs$$ when $$r = 6$$ and ‍$$s = 5$$.

3. Evaluate ‍$$8 - \frac{m}{n} + p^2$$ when $$m = 8$$, $$n = 2$$, $$p = 7$$.

4. Evaluate ‍$$ \frac{9}{g} +2h +5$$ when $$g = 3$$ and $$h = 6$$.

Source: Khan Academy, https://www.khanacademy.org/math/algebra/x2f8bb11595b61c86:foundation-algebra/x2f8bb11595b61c86:substitute-evaluate-expression/e/evaluating_expressions_2
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1. $$=231$$

2. $$=18$$

3. $$=53$$

4. $$=20$$

1. Let's substitute ‍$$j = 2$$ and ‍$$k = 6$$ into the expression.
   • $$3+jk+k^3$$
   • $$=3+(2)(6) + 6^3$$
   • $$=3+12+216$$

   • $$=231$$

2. Let's substitute ‍$$r = 6$$ and ‍$$s = 5$$ into the expression.
   • $$8r - rs$$
   • $$=8(6) - (6)(5)$$
   • $$=48-30$$

   • $$=18$$

3. Let's substitute ‍$$p = 7$$, $$m = 8$$ and ‍$$n = 2$$ into the expression.
   • ‍$$8 - \frac{m}{n} + p^2$$
   • ‍$$=8 - \frac{8}{2} + 7^2$$
   • $$=8 - 4 + 49$$

   • $$=53$$

4. Let's substitute ‍$$g = 3$$ and ‍$$h = 6$$ into the expression.
   • $$\frac{9}{g} +2h +5$$
   • ‍$$=\frac{9}{3} +2(6) +5$$
   • $$=3+12+5$$

   • $$=20$$