РЕШЕНИЕ:

2x²​+11x+15 =0

D = ( 11)² − 4∙2∙15= 121 – 120 = 1 = 1sup]2[/sup]

x₁ = ( –11+1)/4 = – 10 /4 = – 2.5

x₁ = ( –11−1)/4 = – 12/4= – 3

2x²​+11x+15 = 2(x + 3)(x−( – 2.5))

2x²​+11x+15 = 2(x+3)(x − a)

a = – 2.5

Ответ: – 2.5

РЕШЕНИЕ:

x²​+17x+72 =0

D = ( 17)² − 4∙1∙72= 289 – 288 = 1 = 1sup]2[/sup]

x₁ = ( –17+1)/2 = – 16 /2 = – 8

x₁ = ( –17−1)/2 = – 18/2 = – 9

x²​+17x+72 = (x + 9)(x−( – 8))

x²​+17x+72=(x+9)(x−a)

a = – 8

Ответ: – 8

РЕШЕНИЕ:

4x²​+29x − 63 =0

D = ( 29)² − 4∙4∙(−63) = 841 + 1008 = 1849 = 43²

x₁ = (−29+43)/8 = 14/8 = 1.75

x₁ = (−29−43)/8 = −72/8 = −9

4x²​+29x − 63 = 4(x+9)(x − a)

4x²​+29x − 63 = 4(x+9)(x − 1.75)[/b ]

a = 1.75

[b]Ответ: 1.75

РЕШЕНИЕ:

2x^2​− 13x+15 =0

D = ( – 13)² − 4∙2∙15= 169 – 120 = 49 = 7sup]2[/sup]

x₁ = ( 13+7)/4 = 20 /4 = 5

x₁ = ( 13−7)/4 = 6/4= 1.5

2x^2​− 13x+15 = 2(x – 5)(x− 1.5)

2x^2​− 13x+15=2(x − 5)(x − a)

a = 1.5

Ответ: 1.5