Solve these pairs of simultaneous equations: c)

Use substitution

From second equation:-

x = 13 - 5y,                   Substitute for x in the first eqaution:

(13 - 5y)^2 + y^2 = 13

169 -130y + 25y^2 + y^2 - 13 = 0

26y^2  - 130y + 156  = 0

26(y^2 - 5y + 6) = 0

26(y - 3)(y - 2) = 0

y = 2 , y = 3

From the second equation when y = 2, x =  13 - 5(2) = 3

and when y = 3,  x = 13 - 5(3) = -2

So the solution is   [3, 2} and {-2, 3}

unpaid balance is : $149.99-$50 = $99.99 new balance = 149.99+2.62-50 = $102.61 finance charge = 99.99- 0.21/12= $1.75 new balance = 99.99+1.75 = $101.74 average daily balance method average daily balance= 3399.70/30 = $113.32 finance charge = $ 0.21/12ă—113.32 = $1.98 new balance = $149.99-50+1.98 = $101.97