Select all the expressions that simplify to a positive number. 13 – 25
–10.5 + 11
(–30) ÷ (–10)
4.25 ⋅ (–1.25)
–10 + (–18)

In trapezoid efgh, m∠hef=(4x2+16)∘ and m∠gfe=(5x2+12)∘. find the value of x so that efgh is isosceles.

Which of the following represents the length of a diagonal of this trapezoid?

$5400 is? invested, part of it at 11? % and part of it at 8? %. for a certain? year, the total yield is ? $522.00. how much was invested at each? rate?