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Linear Equations (Advanced)

Harder items at competition-adjacent depth.

Phase 2 · SAT Math

Linear Equations: core idea

Parameter constraints on solutions.

Example problem: hint and answer

Solve the system 2x+3y=192x+3y=19 and 5x−3y=235x-3y=23.

Hint: Add the equations to eliminate yy. Answer: x=6,y=7/3.

Practice (9 problems — type your answers)

  • 1. A 240240-mile trip is driven partly at 5050 mph and partly at 7070 mph. If it takes 44 hours, how many miles were driven at 5050 mph?

  • 2. The line through (a,4)(a,4) and (6,10)(6,10) has slope 32\frac32. Find aa.

  • 3. Solve ∣3x−8∣=13|3x-8|=13. Give the negative solution.

  • 4. A fundraiser has adult tickets at 1212 dollars and student tickets at 77 dollars. It sells 8383 tickets for 771771 dollars. How many adult tickets were sold?

  • 5. For what value of cc does y=cx−2y=\frac{c}{x-2} pass through (5,4)(5,4)?

  • 6. If 2x+1x−3=5\frac{2x+1}{x-3}=5, find xx.

  • 7. The solutions to ax+9=3(x+5)ax+9=3(x+5) are all real numbers. Find aa.

  • 8. A tank is 25\frac25 full. After 1818 gallons are added, it is 34\frac34 full. What is its capacity?

  • 9. The mean of xx, x+4x+4, and 3x−23x-2 is 1818. Find xx.

Linear Equations Practice Problems — Advanced