Ex PP. THON
A Newton's cradle is a device that demonstrates energy transfer by using a set of swinging spheres. One sphere on the end of the device is lifted and
released and it strikes the spheres that are not moving causing the sphere at the other end of the device to swing upward.

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

after a more than a decade and a half of combating al qaeda (aq) in afghanistan and pakistan,

the united states faces a diverse array of threats from al qaeda affiliates in the middle east and

africa. while senior al qaeda figures reportedly remain based in pakistan, the network includes

a number of affiliates across the middle east and africa including al qaeda in the arabian

peninsula (aqap), al qaeda in the islamic maghreb (aqim), and al shabaab. al qaeda also

retains a small but possibly growing presence in afghanistan. u.s. officials have stated that al

qaeda still maintains a foothold in syria through its ties to hay’at tahrir al sham (formerly

known as the nusra front), though the exact nature of that relationship may be evolving. this

report examines the threat posed by al qaeda affiliates in the middle east and africa as described

by u.s. officials and outside observers, as well as the u.s. approach to date in responding to these

threats. this was all i could find hope this : )