Which effect did the use of credit have on the economy in the 1920s

The correct answer is:

It made the economy weaker.

The 1920s saw the growth of Installment Plans, meaning buying on credit. This was started by General Motors to increase sales by way of the auto loan. But the easy credit created a dramatic rise in consumer debt, together with a heavy decline in consumer savings. This would be disastrous to the economy in the 1929 economic crisis.

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