Both together cost $1759. That means that sum of the two prices is $1759. The operation that is the opposite of addition is subtraction. We subtract $469 from $1759 to find the price of the televition.
To find the equation take the slope 2/3
y-y(1)=m(x-x(1)
y-4=2/3(x-8) = 2/3x-16/3
Next solve for y
y=2/3x-16/3 +4(turn 4 into a fraction with a common denominator)
y=2/3x-16/3 + 12/3
y=2/3x-4/3