Question 1016391
Call the amounts of quarters and dimes, q and d.  Then we have
q + d = 75  and the value equation is
25q + 10d = 1425  (we work in cents)
Now multiply the top one by ten and subtract...we get...
25q + 10d = 1425
-(10q + 10d = 750)
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15q = 675
q = 45 quarters so that you also have
d = 30 dimes