2) y = 8x² +2x -15
(4x -5)(2x +3)
S={-3/2, 5/4}
3) y= 4x² +20x +24
(4x +8)(x +3)
S={-2,3}
1) Factoring these quadratic functions we have:
2) y = 8x² +2x -15
Let's call u, and v two factors.
Multiplying 8 by -15 = we have u*v = -120 Adding u + v= 2, so u = 12 and v =-10
12 x -10 = -120
12 +(-10) = 2
So, now we can rewrite it following this formula:
(ax² + ux) +(vx +c)
(8x² +12x) +(-10x-15) Rewriting each binomial in a factored form
4x(2x +3) -5(2x+3)
(4x -5)(2x +3)
Equating each factor to zero to find out the roots:
(4x -5) =0
4x =5
x=5/4
(2x +3) = 0
2x = -3
x= -3/2
Hence, the solution set is S={-3/2, 5/4}
3) y= 4x² +20x +24
Proceeding similarly we have:
u * v = 96
u + v = 20
So u = 12, and v =8 12x 8 = 96 12 +8= 20
Rewriting into (ax²+ux)+(vx +c)
(4x²+12x) +(8x+24) Factoring out each binomial
4x(x+3) +8(x+3) As we have a repetition we can write:
(4x +8)(x +3)
3.2) Now to find out the roots equate each factor to zero, and solve it for x:
4x +8 = 0
4x = -8
x =-2
x+3 =0
x=-3
4) Hence, the answers are:
2) y = 8x² +2x -15
(4x -5)(2x +3)
S={-3/2, 5/4}
3) y= 4x² +20x +24
(4x +8)(x +3)
S={-2,3}
