Linear equations in one variable
Answers are for parents and teachers.
1
Five less than three times a number is 16. Write an equation and solve it.
3x − 5 = 16, 3x = 21, x = 7.
2
Solve 4x + 9 = 1 in Z.
4x = −8, so x = −2. The solution set is {−2}.
3
Solve 6x − 5 = 2x + 11.
4x − 5 = 11, 4x = 16, x = 4.
4
Solve 3x = 10 in N and in Q.
x = 10/3. In N the solution set is ∅. In Q it is {10/3}.
5
Three consecutive even numbers add up to 54. Find them.
x + (x + 2) + (x + 4) = 54, 3x + 6 = 54, x = 16. The numbers are 16, 18 and 20.