Hints:
-Square both sides
-Solve the equation for x
-Remember when dividing by - or multiplying by - we multiply both sides and in inequalities, we switch the sign e.g, if it is < then it will be > if being multiplied or divided by -)
-If real numbers find intervals
+128408 √ [x^2 - 13x + 12] ≤ 5 - x square both sides
x^2 - 13x + 12 ≤ x^2 - 10x + 25 simplify
-3x ≤ 13 divide both sides by -3, reverse the inequality sign
x ≥ - 13/3
But we also must have that
x^2 - 13x + 12 ≥ 0
(x - 12) ( x - 1) ≥ 0
The solutions to this are
(-inf, 1 ] U [12, inf)
We must take the most restrictive interval....this is
-13/3 ≤ x ≤ 1
