Question 35165
D=Q+3 & 10D+25Q=170 OR SUBSTITUTING (Q+3) FOR Q IN THE SECOND EQUATION WE HAVE

10(Q+3)+25Q=170 OR 10Q+30+25Q==170 OR 35Q=140 OR Q=4 THEREFORE D=Q+3 OR D=7
PROOF 10*7+4*25=170 OR 70+100=170 OR 170=170