Answer:
Step-by-step explanation:
An expression means that we don't know enough to create an equation. So, this means we will mostly be using variables.
John runs r amount every day. We need to create an expression for if he runs r amount for 4 days.
r = how much he runs per day
4 = how many days he runs
z = how much he runs this week
This is your expression!
This looks complicated
lets simplify both sides
By multiplying top and bottom by the conjugate:-
left side = (5-3i)(x + iy) (4+5i) (5-3i)(x + iy) (4+5i)
------------------------ = ------------------------
(4-5i)(4+5i) 41
right side = (2 + i + 3-4)(2+i - 3 + 4i) (by Difference of 2 squares)
= 5-3i)(-1 + 4i)
so as left side = right side
(5-3i)(x+yi)(4+5i) = 41 (5-3i)(-1+5i)
5-3i is common so:-
(x + iy)(4+5i) = 41(-1+5i)
4x +5xi + 4yi - 5y = -41 + 205i
4x - 5y + (5x + 4y)i = -41 + 205i
EQuating coefficients we are left with the system of equations
4x - 5y = -41
5x + 4y = 205
solving this gives x = 21 and y = 25
