Answer:
Step-by-step explanation:
note :
the discriminat of each quadratic equation : ax²+bx+c=0 ....(a ≠ 0) is :
Δ = b² -4ac
1 ) Δ > 0 the equation has two reals solutions : x = (-b±√Δ)/2a
2 ) Δ = 0 : one solution : x = -b/2a
3 ) Δ < 0 : no reals solutions
in this exercice : 4x²-30x+45=0
a= 4 b= -30 c=45
Δ = (-30)² - 4(4)(45) = 900 - 720 = 180.......continu
