Answer:
Dark matter is just matter whose particles do not absorb reflect or emit light and can't be seen directly. We know of its existence because of its effects on objects that we c a n see. It's density formula is 2.241×10⁻²⁷ kg/m³
Step-by-step explanation:
Answer: 40.192 cm
Step-by-step explanation:
the formula for circumference is 
In this case we are using 3.14 for pi and the radius is 6.4

Formula is
ₙCₖ = (n!)/( k!*(n-k)! )
so ₇C₃ = (7!) / (3! * (7-3)!)
and 7! = 7 * 6 * 5 * 4 * 3 * 2 * 1
= (7 * 6 * 5 * 4 * 3 * 2 * 1)/(3 * 2 * 1 * 4!)
= (7 * 6 * 5 * 4)/(4!)
= (7 * 6 * 5 * 4)/(4 * 3 * 2 * 1)
= (7 * 6 * 5 )/(6 * 1)
= (7 * 5 )/( 1)
= 35
Answer:
so the expression should be -2+7+2(2-(-3))