X^2 = 9x + 6
x^2 - 9x - 6 = 0
use quadratic formula : (-b (+-) sqrt b^2 - 4ac) / (2a)
a = 1, b = -9, c = -6
now we sub
x = (-(-9) (+-) sqrt -9^2 - 4(1)(-6)) / 2(1)
x = 9 (+-) sqrt 81 + 24)/2
x = 9 (+-) sqrt 105) / 2
x = 9/2 + 1/2 sqrt 105 or x = 9/2 - 1/2 sqrt 105
For a system of two variables and two equations, each equation will be a linear graph, and where the lines intersect is the solution as an ordered pair (x,y). If the lines don’t intersect (they’re parallel) so there is no unique solution.
86.
Fatima has 40
Nora has “6 + (40 x 2)”
6+(80) = 86
