Question

Solve each of the quadratic inequalities and express the solution sets using interval notation.

please answer only no. 6-10
asap, thank you! ​

Answer 1

4x²-20x+25<0

b²-4ac = (-20)²-4(4*25)=0

Δ =0; one solution : -b/2a = 40/8 =5/2

the inequality is true for all x ∈∅

a²+4a-21<0

b²-4ac = (4)²-4(1*-21)=100

Δ=100;

(-b-√Δ)/2a =(-4-10)/2= -7

(-b+√Δ)/2a=(-4+10)/2 =3

The inequality is there fore true for all a in ]-7;3[`