Which shows the best estimate of the quotient of 523 divided by 67?

Which of the following is correct interpretation of the expression -4+13

If square root x = -7, then x= -49 true or false

The perimeter of △cde is 55 cm. a rhombus dmfn is inscribed in this triangle so that vertices m, f, and n lie on the sides cd , ce , and de respectively. find cd and de if cf=8 cm and ef=12 cm. the answer is not cd=20 and de=15. i have tried that one, it does not work.