Answer:
Zoe's number is 6
Step-by-step explanation:
Let the number be 'n'
a) Multiply 'n' by 3 ⇒ n*3 = 3n
Add 4 to '3n' ⇒ 3n + 4
Add 5 to 'n' ⇒ n +5
Multiply (n+ 5) by 2 ⇒ (n +5)*2 = 2n + 5*2 = 2n + 10
3n + 4 = 2n + 10
b) 3n + 4 = 2n + 10
Subtract 4 form both sides
3n = 2n + 10 - 4
3n = 2n + 6
Subtract 2n from both sides
3n - 2n = 6