Examples with solutions for Variables and Algebraic Expressions: Applying the formula

Exercise #1

18x7+4x98x=? 18x-7+4x-9-8x=\text{?}

Video Solution

Step-by-Step Solution

To solve the exercise, we will reorder the numbers using the substitution property.

18x8x+4x79= 18x-8x+4x-7-9=

To continue, let's remember an important rule:

1. It is impossible to add or subtract numbers with variables.

That is, we cannot subtract 7 from 8X, for example...

We solve according to the order of arithmetic operations, from left to right:

18x8x=10x 18x-8x=10x 10x+4x=14x 10x+4x=14x 79=16 -7-9=-16 Remember, these two numbers cannot be added or subtracted, so the result is:

14x16 14x-16

Answer

14x16 14x-16

Exercise #2

7.34a+2.3+8a=? 7.3\cdot4a+2.3+8a=\text{?}

Video Solution

Step-by-Step Solution

It is important to remember that when we have numbers and variables, it is impossible to add or subtract them from each other.

We group the elements:

 

7.3×4a+2.3+8a= 7.3×4a + 2.3 + 8a =

29.2a + 2.3 + 8a = 

37.2a+2.3 37.2a + 2.3

 

And in this exercise, this is the solution!

You can continue looking for the value of a.

But in this case, there is no need.

Answer

37.2a+2.3 37.2a+2.3

Exercise #3

3x+4x+7+2=? 3x+4x+7+2=\text{?}

Video Solution

Answer

7x+9 7x+9

Exercise #4

3z+19z4z=? 3z+19z-4z=\text{?}

Video Solution

Answer

18z 18z

Exercise #5

7a+8b+4a+9b=? 7a+8b+4a+9b=\text{?}

Video Solution

Answer

11a+17b 11a+17b

Exercise #6

13a+14b+17c4a2b4b=? 13a+14b+17c-4a-2b-4b=\text{?}

Video Solution

Answer

9a+8b+17c 9a+8b+17c

Exercise #7

a+b+bc+9a+10b+3c=? a+b+bc+9a+10b+3c=\text{?}

Video Solution

Answer

10a+11b+(b+3)c 10a+11b+(b+3)c

Exercise #8

35m+9n48m+52n=? 35m+9n-48m+52n=?

Video Solution

Answer

61n13m 61n-13m

Exercise #9

8y+4534y45z=? 8y+45-34y-45z=\text{?}

Video Solution

Answer

26y+4545z -26y+45-45z

Exercise #10

5a+3a+8b+10b=? 5a+3a+8b+10b=\text{?}

Video Solution

Answer

8a+18b 8a+18b

Exercise #11

3.43.4a+2.6b7.5a=? 3.4-3.4a+2.6b-7.5a=\text{?}

Video Solution

Answer

3.410.9a+2.6b 3.4-10.9a+2.6b

Exercise #12

7.8+3.5a80b7.8b+3.9a=? 7.8+3.5a-80b-7.8b+3.9a=\text{?}

Video Solution

Answer

7.8+7.4a87.8b 7.8+7.4a-87.8b

Exercise #13

39.3:4a+5a+8.2+13z=? 39.3:4a+5a+8.2+13z=\text{?}

Video Solution

Answer

13z+8.2+9.825a+5a 13z+8.2+\frac{9.825}{a}+5a

Exercise #14

5.6x+7.9y+53xy+12.1x=? 5.6x+7.9y+53xy+12.1x=\text{?}

Video Solution

Answer

17.7x+53xy+7.9y 17.7x+53xy+7.9y

Exercise #15

14a+13x+24a+18+38=? \frac{1}{4}a+\frac{1}{3}x+\frac{2}{4}a+\frac{1}{8}+\frac{3}{8}=\text{?}

Video Solution

Answer

34a+13x+12 \frac{3}{4}a+\frac{1}{3}x+\frac{1}{2}

Exercise #16

38a+149b+119b+68a=? \frac{3}{8}a+\frac{14}{9}b+1\frac{1}{9}b+\frac{6}{8}a=\text{?}

Video Solution

Answer

118a+223b 1\frac{1}{8}a+2\frac{2}{3}b