Medium
Solve the pair of linear equations for x: 4x + 4y = -20 and 2x + -1y = -4.
Explanation
Explanation
Using the elimination method: multiply the first equation by -1 and the second by 4, then subtract to eliminate y. Solving gives x = -3 (and correspondingly y = -2). You can verify: 4(-3) + 4(-2) = -20 ✓ and 2(-3) + -1(-2) = -4 ✓.
PRO TIP
Re-check your working by substituting the answer back into the original question.