Question

It is exponent laws. My teacher said x is 3 but I don't get why

Answer 1

Exponent laws

one of them goes liek this

if you have bⁿ=bᵃ where b=b, then n=a

so, try to match bases

2ˣ⁺⁴=128
128=2⁷

we have
2ˣ⁺⁴=2⁷
2=2
therefor
x+4=7
now subtract 4 from both sides
x=3