Answer:
[tex]5x^{2} +7x =15[/tex]
[tex]0.25x^{2} +0.8x-8=0[/tex]
Step-by-step explanation:
Given equations : [tex](x+8)(x+9)[/tex]
[tex]5x^{2} +7x =15[/tex]
[tex]0.25x^{2} +0.8x-8=0[/tex]
[tex](x-3)^{2}=36[/tex]
Solution:
A) [tex]5x^{2} +7x =15[/tex]
It is not appropriately solved by using the quadratic formula because the solution is direct
The solution is x=-8 and x=-9
B) [tex]5x^{2} +7x =15[/tex]
⇒ [tex]5x^{2} +7x-15=0[/tex]
It is appropriately solved by using the quadratic formula because the solution is not direct
C) [tex]0.25x^{2} +0.8x-8=0[/tex]
It is appropriately solved by using the quadratic formula because the solution is not direct
D) [tex](x-3)^{2}=36[/tex]
⇒[tex](x-3)^{2}=6^2[/tex]
⇒[tex](x-3)=6[/tex]
⇒[tex]x=6+3[/tex]
⇒[tex]x=9[/tex]
It is not appropriately solved by using the quadratic formula because the solution is direct.
Hence Option B and C are the two equations would be most appropriately solved by using the quadratic formula.
