Q. Which equation has the same solution as x2−5x−20=7 ?(x−2.5)2=33.25(x+2.5)2=33.25(x−2.5)2=20.75(x+2.5)2=20.75
Simplify Equation: First, let's simplify the given equation x2−5x−20=7 by moving all terms to one side to set the equation to zero.x2−5x−20−7=0x2−5x−27=0
Expand Option 1: Now, let's look at the provided options to see which one, when expanded, will give us the same quadratic equation as x2−5x−27=0. We will start by expanding the first option.Option 1: (x−2.5)2=33.25Expanding (x−2.5)2 gives us:x2−2×2.5×x+2.52=33.25x2−5x+6.25=33.25Now, subtract 33.25 from both sides to set the equation to zero:x2−5x+6.25−33.25=0x2−5x−27=0This matches our simplified equation.
Check Option 2: Let's check the other options to ensure they do not also match the simplified equation.Option 2: (x+2.5)2=33.25Expanding (x+2.5)2 gives us:x2+2⋅2.5⋅x+2.52=33.25x2+5x+6.25=33.25Subtracting 33.25 from both sides:x2+5x+6.25−33.25=0x2+5x−27=0This does not match our simplified equation.
Check Option 3: Option 3: (x−2.5)2=20.75Expanding (x−2.5)2 gives us:x2−2×2.5×x+2.52=20.75x2−5x+6.25=20.75Subtracting 20.75 from both sides:x2−5x+6.25−20.75=0x2−5x−14.5=0This does not match our simplified equation.
Check Option 4: Option 4: (x+2.5)2=20.75Expanding (x+2.5)2 gives us:x2+2⋅2.5⋅x+2.52=20.75x2+5x+6.25=20.75Subtracting 20.75 from both sides:x2+5x+6.25−20.75=0x2+5x−14.5=0This does not match our simplified equation.
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