Which best describes the muslim presence in north africa in the late seventh and early eighth centuries?
a. trade connections gave islam a presence in cities and ports where merchants went.
b. muslim missionaries first traveled throughout north africa, and armies followed later.
c. islam slowly converted the peoples of north africa without a military takeover.
d. muslim armies carried their faith west across the top of the entire continent.

was a long, primarily nonviolent series of events to bring full civil rights and equality under the law to all americans. the era has had a lasting impact on united states society, in its tactics, the increased social and legal acceptance of civil rights, and in its exposure of the prevalence and cost of racism. in the south violence and fraud in southern elections from 1868 to 1876, which had reduced black voter turnout and enabled southern white democrats to regain power in state legislatures across the south

the perimeter of a triangle is 69 cm. side a is 5 cm shorter than side b. side c is twice as long as side a. find the length of each side. i need to know how to do it in 2 equations.  

equations:

a = b-5

c = 2a

a + b + c = 69