Math · 1
Solve for x: 3x + 5 = 20
Answer
5
3x + 5 = 20; 3x = 15; x = 5. Linear equations form the foundation of algebra and appear in systems of equations used across physics, economics, engineering, and business.
💡 Did you know?
Netflix uses linear equations to predict when you'll finish a series based on your viewing patterns—solving for 'x' powers your personalized recommendations.
Other options people guess
- 8
- 10
- 15
Topics
- algebra
- linear equations
- variables
Know your math trivia?
Play a free Math quiz and see how many you get right — no signup needed to start.
More Math facts
Math
What is the slope of a line passing through points (0,0) and (4,8)?
Wheelchair ramps require a slope of 1:12 to be safe and legal—steeper slopes, determined by rise/run math, can cause wheelchairs to tip backward.
Math
What is 5! (5 factorial)?
There are 40,320 ways to arrange 8 books on a shelf (8!). For just 13 books, there are more arrangements than there are stars visible in the night sky.
Math
What is 1/2 + 1/4?
The Babylonians used fractions with denominator 60 five thousand years ago—that's why an hour has 60 minutes, a legacy of ancient fraction math.
Math
What is the distance between points (0,0) and (3,4) on a coordinate plane?
GPS satellites use the distance formula constantly to triangulate your location from multiple satellites orbiting Earth—you carry this 2,000-year-old math in your pocket.
Math
What is 45 ÷ 9?
Division was considered black magic in medieval Europe. Merchants who could divide numbers quickly were thought to have supernatural abilities.
Math
What is the volume of a rectangular prism with dimensions 2 × 3 × 4?
Shipping containers use volume formulas to maximize cargo—a 20-foot container holds exactly 33 cubic meters, calculated to fit on ships with mathematical precision.