Answer:
A) Therefore laser1 has the maximum closest to the central maximum 
B) Δₓ = 0.8
Step-by-step explanation:
A) The expression for the constructive interference of a double slit is 
 d sin θ = m λ
 
let's use trigonometry to find the angle 
 tan θ = y / L 
in interference phenomena the angles are small 
 tan θ = sin θ / cos θ = sin θ 
 sin θ = y / L 
we subjugate 
 d y / L = m λ 
 y = m λ L / d 
let's apply this equation for each case 
a) Lares 1 has a wavelength λ₁ = d / 20, the screen is at L = 6.00 m 
they ask us for the first axiom m = 1, 
let's calculate 
 y₁ = 1 (d / 20) 6.00 / d 
 y₁ = 0.3 
Laser 2, λ₂ = d / 15 
 λ₂ = 1 (d / 15) 6.00 / d 
 λ₂ = 0.4 
Therefore laser1 has the maximum closest to the central maximum 
b) let's find the distance of each requested value 
second maximum m = 2 of laser 1 
 
 yi '= 2 (d / 20) 6 / d 
 y1 '= 0.6 
3rd minimum of laser 2 
the expression for destructive interference is 
 d sinθ = (m + 1/2) lam 
 y = (m ) λ L / d 
in this case m = 3 
let's calculate 
 y2 '= (3+0.5) (d / 15) 6 / d 
 y2 '=21/15 
 
They ask us for the dalt of these interference 
 Δₓ = y3 -y2' 
 Δₓ = 21/15 - 0.6 
 Δₓ = 0.8