>>3250791) left page = x, right page = x+1
x(x+1) = 420
x^2+x-420 = 0
(x+21)(x-20) = 0
x = 20 or -21, but pages are positively numbered, so x = page 20
2) You have to know that 1999 is prime (idk how) and 2 is prime (easy)
3) Parallel sides of rectangle are equal. If we give one pair or sides length x and the other pair length y, then 2x+y = 88cm and x+2y = 80cm. y = 88cm-2x, so x+176cm-4x = -3x+176cm = 80cm, so 3x = 96cm, so x = 32cm. plug in 32cm in 2x+y=88cm, and 64cm + y=88 cm and y=24 cm. There are two sides of both lengths y and x, so perimeter = 24cm*2+32cm*2 = 112 cm
4) x = the average score
Amanda = x-5
Barb = x+8
Colin = 82
Average of those three people = x = ((x-5)+(x+8)+82)/3, so x=(2x+85)/3, so 3x = 2x+85, so x=85
5) The overlap is made of two different triangles, which you can figure out multiple ways. The rest of ABC outside the overlap is two triangles of the same size, so the total area of ABC is 24 cm
