Alright, so we'd use the combinations with repetition formula, so we choose from 4 schools to distribute to and distribute 8 blackboards. It's then
( 8+4-1)!/8!(4-1)!=11!/(3!*8!)=165
For at least one blackboard, we first distribute 1 to each school and then have 4 blackboards left, getting (4+4-1)!/4!(4-1)!=7!/(4!*3!)=35

- two acute angle=<JBC and <JBG
<JBC and <JBG(because these two angle are 45°)
by definition of acute angle any angle which is between 0°to 90° then it will acute angle
- two straight line=FH ,.AD
- two right angle=<GBD and <GBA
- two obtuse angle=<BCH and <BGF
Answer:
The answer is i think -12*2
Step-by-step explanation: