Answer:
Step-by-step explanation:
<em>7).</em> x + y = 4 ⇒ y = 4 - x -----> xy = - 96
x(4 - x) = - 96 ⇔ x² - 4x - 96 = 0
D = ( - 4)² - 4(1)(- 96) = 400 = (20)²
= (- ( - 4) - 20) ÷ 2(1) = - 8
= ( - ( - 4) + 20) ÷ 2 = 12
Numbers are <em>- 8</em> and <em>12</em>
<em>8).</em> <em><u>It's your turn now. You can do it</u></em>
<em>9).</em> x² - 5x + 3 = 0
0 <
< 1
4 <
< 5
<em>10).</em> - x² + 3x + 1 = 0
-1 <
< 0
3 <
< 4
<em>11).</em> x² + 2x - 2 = 0
- 3 <
< - 2
0 <
< 1