800+900×25-65(89+5)-12÷67-7​

As there is Bracket lats solve it first but as there is '-' sign before the bracket sign in the bracket will change. so we will have,

'800+900×25-65(89-5)-12÷67-7'

Solving the bracket gives us:

'800+900×25-65(84)-12÷67-7'

Now avoiding the Bracket:

'800+900×25-5460-12÷67-7'

Now first we have to do MUltiplication, so we will get,

'800+22500-5460-12÷67-7'

Now let's do the division, so we will get,

'800+22500-5460-0.17-7'

Now lets do the additions and subtractions we will get,

tube or goog would be a great resource to with that question