Easy Algebra Step-by-Step

156 Easy Algebra Step-by-Step

Step 7. Check your answer by substituting −5 for x in the original equation,

5 x+ 9 = 3 x − 1

Substitute −5 for x on the left side of the equation: 5x+ 9 = 5 (−5) + 9 =

−25 + 9 = −16. Similarly, on the right side, you have 3x − 1 = 3(−5) −

1 = −15 − 1 = −16. Both sides equal −16, so −5 is the correct

answer.

b. 4(x − 6) = 40

Step 1. Use the distributive property to remove parentheses.

4 x − 24 = 40

Step 2. 24 is subtracted from the variable term, so add 24 to both sides.

4x − 24 + 24 = 40 + 24

Step 3. Simplify both sides by combining constant terms.

4 x= 64

Step 4. You want the coeffi cient of x to be 1, so divide both sides by 4.

46 x 4

44

=

Step 5. Simplify.

x = 16

Step 6. Check your answer by substituting 16 for x in the original equation,

4(x − 6) = 40.

Substitute 16 for x on the left side of the equation: 4(x − 6) = 4 (16 −

6) = 4(10) = 40. On the right side, you have 40 as well. Both sides

equal 40, so 16 is the correct answer.

c. −3x − 7 = 14

Step 1. 7 is subtracted from the variable term, so add 7 to both sides.

−3x − 7 + 7 = 14 + 7

Step 2. Simplify both sides by combining constant terms.

− 3 x = 21

Step 3. You want the coeffi cient of x to be 1, so divide both sides by −3.

−

−

=

32 x 1

33 −