Giving the formula for the perimeter of a rectangle, a =1/2h(b1+b2), which answer would you get if you solve for b1

The equation x2 – 1x – 90 = 0 has solutions {a, b}. what is a + b?

Kayla wants to find the width, ab, of a river. she walks along the edge of the river 65 ft and marks point c. then she walks 25 ft further and marks point d. she turns 90° and walks until her location, point a, and point c are collinear. she marks point e at this location, as shown. (a) can kayla conclude that δ and δ are similar? why or why not? (b) suppose de = 15 ft. what can kayla conclude about the width of the river?

Determine which expressions represent real numbers and which expressions represent complex number. asaaap! plis!