“SAT-Level Algebra Trick 😳”solve it before the answer appeared? #maths #mathproblems #satmath

追加: 2026-05-16

[00:00:00]At first, this equation looks difficult because it contains both X and square root X together. But instead of solving it directly, use a substitution method.

[00:00:09]Let square root X be equal to Y. Since X is equal to Y squared, replace X in the equation with Y squared. The equation now becomes 2 Y squared plus Y equals 6.

[00:00:20]Move all terms to one side to get 2 Y squared plus Y minus 6 equals 0. Now factorize the quadratic equation carefully. It becomes bracket 2 Y minus 3 bracket multiplied by bracket Y plus 2 bracket equals 0. Therefore, Y equals 3 by 2 or Y equals minus 2. But square root X cannot be negative, so Y equals minus 2 is rejected. Since Y equals square root X, we get square root X equals 3 by 2.

[00:00:48]Finally, square both sides giving X equals