Which two equations would be most appropriately solved by using the quadratic formula? Select each correct answer. (x+8)(x+9)=0 5x2+7x=15 0.25x2+0.8x−8=0 (x−3)2=36
Accepted Solution
A:
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 directThe solution is x=-8 and x=-9B) [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 directC) [tex]0.25x^{2} +0.8x-8=0[/tex]It is appropriately solved by using the quadratic formula because the solution is not directD) [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.