They are right except for 12. i think it is C but i could be wrong.
(predicted value - exact value)/exact value * 100
(31 - 34)/34 * 100 = 8.8%
Answer:
- -6x² - 6 = -7x - 9
- -6x² + 7x - 6 + 9 = 0
- -6x² + 7x + 3 = 0
- 6x² - 7x - 3 = 0
<u>Discriminant:</u>
- D = (-7)² - 4*6*(-3) = 49 + 72 = 121
<u>Since D > 0, there are 2 real solutions:</u>
- x = (- (-7) ±√121 )/12
- x = (7 ± 11)/12
- x = 1.5, x = -1/3
1.8- 3.7x = 4.2x + 0.3
Move 4.2x to the other side
Sign changes from +4.2x to -4.2x
1.8-3.7x-4.2x= 4.2x-4.2x+0.3
1.8-3.7x-4.2x= 0.3
1.8-7.9x= 0.3
Move 1.8 to the other side
Sign changes from +1.8 to -1.8
1.8-1.8-7.9x= 0.3-1.8
-7.9x= 0.3-1.8
-7.9x= -1.5
divide both sides by -7.9
-7.9/-7.9x= -1.5/-7.9
x= 0.18987341
Answer: x= 0.18987341
