Question

A) [(16-2x2+4x2):a]+3=8
b) 5+15x(25-75:5+25:a)=1150:5
c) 3+2x{[72-12x(a-3)]-9x4

Answer 1

a) [(16-2x2+4x2):a]+3=8 [(16-4+8):a]+3=8
[(16-4+8):a]+3=8
20:a+3=8⇒    20:a=8-3⇒    20:a=5⇒    a=$a= \frac{20}{5}$=4

b) 5+15x(25-75:5+25:a)=1150:5
5+15(25-15+25:a)=230
15(10+25:a)=230-5
10+25:a=15
25:a=5
a=5

c) 3+2x{[72-12x(a-3)]-9x4
3+2x{[72-12x(a-3)]-9x4
2(108-12a)-36=0
108-12a=36:2
12a=108-18
a=90:12=45:6
a=15:2

Answer 2

a) [(16-2x2+4x2):a]+3=8
(16-4+8):a=8-3
20:a=5
a=4

b) 5+15x(25-75:5+25:a)=1150:5
15x(25-15+25:a)=230-5
15x(10+25:a)=225
10+25:a=15
25:a=5
a=5

c) 3+2x{[72-12a+36)]-36=0
2(108-12a)-36=0
2(108-12a)=36
108-12a=18
12a=108-18=90
a=90/12=45/6=15/2