Writing Expressions & Equations
Write an expression: “5 more than a number x.”
x + 5
Simplify: 4x + 3x
7x
Evaluate: x + 9 when x = 4
13
Solve: x + 5 > 10
x > 5
The relationship is given by:
y = 2x + 3
What is the value of y when x = 4?
y = 2(4) + 3 = 11
Write an expression: “Twice a number minus 7.”
2x − 7
Simplify: 6y – 2y + 5
4y + 5
Solve: x + 6 = 14
x = 8
Write an inequality: “A number is at least 12.”
x ≥ 12
Each smoothie costs $4. x = number of smoothies, y = cost
x | 1 | 2 | 5 |
y | ? | ? | ? |
Write an equation: “A number decreased by 12 is 45.”
x − 12 = 45
Simplify: 3a + 7 + 2a – 4
5a + 3
Solve: 3x = 27
x = 9
Solve: 3x ≤ 21
x ≤ 7
A bike rental shop charges a $10 fee plus $5 per hour.
Hours (x) | 1 | 2 | 3 |
Cost (y) | ? | ? | ? |
A student has read 120 pages and reads 25 pages per day. Write an expression for total pages read after d days.
120 + 25d
Simplify: 5x + 2(3x + 4)
5x + 6x + 8 = 11x + 8
Which value from the set {4, 5, 6, 8} makes this true?
5x – 10 = 20
x = 6
Graph the solution to: x ≥ 6
A school event starts with 4 organizers. Each ticket sold adds 1 more person attending.
x | 0 | 1 | 2 | 3 |
y | 4 | 5 | 6 | 7 |
A gym charges a $50 sign-up fee and $20 per month.
Equation: C = 50 + 20m
50 = starting fee, 20m = monthly cost, m = number of months
A rectangle has sides (2x + 3) and (x + 5). Write and simplify an expression for the perimeter.
Perimeter = 2(2x + 3) + 2(x + 5)
= 4x + 6 + 2x + 10
= 6x + 16
A streaming service costs $8 per month. You have $64.
Equation: 8m = 64
Solution: m = 8 months
*students may use a different variable
You need at least $200 for a trip. You already have $75 and save $15 per week.
A car travels at a constant rate. After 2 hours it goes 120 miles, after 4 hours it goes 240 miles.