how do I solve the equation x^2 + 7x + 11 = 0, to 3dp?


This is a quadratic equation and there are three ways to solve one. This question specifies that the answer should be left to three decimal places. This tells you that you can not factorise, as your answer would be an integer. The linear x term, 7x, has a odd coefficient, therefore completing the square is not advised. The best method for solving this is by using the quadratic formula. This involves substituting the three coefficients of the quadratic equation into a set formula to find the roots/ solution to the equation. The formula is:x = (-b+/- squareroot(b^2 - 4ac))2*aWhere a is the x^2 coefficient, b is the x coefficient and c is the constant term.The +/- indicates that there are two solutions. The first being when a + is used and the second when a - is used. The two values the calculator returns should be rounded to 3 decimal places and then are the solutions to the question.

JD
Answered by Jamie D. Maths tutor

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