Multiple choice

Solve the following pair of equations : $\displaystyle \frac{3}{5}x-\displaystyle \frac{2}{3}y+1= 0$ $\displaystyle \frac{1}{3}y+\displaystyle \frac{2}{5}x= 4$

  1. $x= 2;y= -1$
  2. $x= 5;y= 6$
  3. $x= 7;y= -4$
  4. $x= 0;y= 5$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The equations are (3/5)x - (2/3)y = -1 and (2/5)x + (1/3)y = 4. Multiplying the second by 2 gives (4/5)x + (2/3)y = 8. Adding this to the first gives (7/5)x = 7, so x = 5. Substituting x=5 into the second equation: 2 + (1/3)y = 4, so (1/3)y = 2, y = 6.

AI explanation

Multiplying the first equation by 15 gives 9x - 10y = -15. Multiplying the second equation by 15 gives 6x + 5y = 60. Multiplying this second result by 2 gives 12x + 10y = 120. Adding this to the first result yields 21x = 105, so x = 5. Substituting x = 5 into 6x + 5y = 60 gives 30 + 5y = 60, so y = 6. The solution is x = 5, y = 6.