Start to solve by substitution: eqn 1 x^2 + y^2 = 25eqn 2 y - 3x = 13 => y = 3x + 13Substitute eqn 2 into 1: x^2 + (3x +13)^2 = 25expand and simplify the equation ...5x^2 + 39x + 72 = 0
(a) Several methods to do this, simplest would be to factorise the quadratic into (x - 4)(x + 2) = 0 and from here see that root occur at x = 4 and x = -2.(b) Substitute x = 0 into the equation 0^2 - 2