solve 25x^2-25x-6=0
1b.
the cost price of a diamond is $120000. Mary sold it to Helen at a profit of r%.
After one year, Helen sold the diamond back to Mary at a profit of r%.
As a result, Mary lost $28800. Find the value of r.
2.
The height of the perimeter of a right-angled triangle are x cm and 40cm
respectively. If the length of its base is 1cm less than twice its height, find the
value of x.
its quite difficult for me,,,,,, please help. Thanks a lot~
更新1:
for 1b, factor method should be used and ans should be r= 20 since r must be a positive value. r^2+100r-2400=0 (r+120)(r-20)=0 r= -120(rejected) or r= 20 Anyway, you did it well and i will give u the marks. Thanks~~~
