^2log5=a ^5log7=b tentukan nilai ^75log28

^5 x 5 x 3 log2 x 2 x 7=log2+log2+7/log 5 + log 5 + log 3
                                   =^5 log2+^5 log2+^5 log3/^5 log5+^5 log5+ ^5 log3
                                   =1/a+1/a+^5 log3/1+1+^5 log3
                                   =2/a+^5 log3/2+^5 log3
insyaAllah benar