Q. Solve the following equation for z.4z+9=z+1z=□
Isolate square root: Isolate the square root on one side of the equation.We have the equation 4z+9=z+1. The square root is already isolated on the left side of the equation.
Square both sides: Square both sides of the equation to eliminate the square root.(4z+9)2=(z+1)2This gives us 4z+9=(z+1)(z+1).
Expand right side: Expand the right side of the equation. 4z+9=z2+2z+1
Move terms to one side: Move all terms to one side to set the equation to zero and form a quadratic equation.0=z2+2z+1−4z−9
Combine like terms: Combine like terms.0=z2−2z−8
Factor quadratic equation: Factor the quadratic equation, if possible.We look for two numbers that multiply to −8 and add to −2. These numbers are −4 and +2.0=(z−4)(z+2)
Solve for z: Solve for z by setting each factor equal to zero.z−4=0 or z+2=0This gives us z=4 or z=−2.
Check solutions: Check both solutions in the original equation to ensure they do not result in taking the square root of a negative number.For z=4: 4(4)+9=4+116+9=525=55=5, which is true.For z=−2: 4(−2)+9=−2+1−8+9=−11=−11=−1, which is false.So, z=−2 is not a valid solution because it does not satisfy the original equation.
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