Which is the better buy?
2 answers:
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Answer:
a) x =3 and x=5
c) x =-1 and
i) x =0 and
Step-by-step explanation:
a)
Given that the quadratic equation
x² - 8x +15 =0
The factors of 15 = 5 × 3
x² - 5x -3x +15 =0
x(x -5) -3(x-5) =0
(x-3)(x-5) =0
x =3 and x=5
c)
3 x² + 10 x +7 =0
⇒ 3x² + 3x + 7x +7 =0
⇒ 3x (x +1) +7(x+1) =0
⇒ (x+1) ( 3 x +7) =0
⇒ x =-1 and
i)
2 x ² + 9 x =0
⇒ x( 2 x + 9) =0
⇒ x =0 and 2 x = -9
⇒ x =0 and