Ex1 please!! Someone can plz help me!

2+3x15-4-2+1x7
=2+45-4-2+7
=47-4-2+7
=43-2+7
=41+7
=48

1) 2+3x15-4-2+1x7
2+45-4-2+7
47-6+7
41+7
48

2) 25+8÷4x2x2-1
25+2x4-1
25+8-1
33-1
32

3) 12+(3+2)x4-4x5
12+5x4-4x5
12+20-20
32-20
12

4) 25-[3x(6-2)x2-1]
25-[3x4x2-1]
25-[24-1]
25-23
2

5) (11-3x2)x(2x2+1)
(11-6)x(4+1)
5x5
25

6) 16-(12-(6-(4-3)))
16-(12-(6-1))
16-(12-5)
16-7
9

Voilà j'espère que sa t'aideras