Exercise 55 Page 767

We will use the Quadratic Formula to solve the given quadratic equation. ax^2+ bx+ c=0 ⇕ x=- b± sqrt(b^2-4 a c)/2 a Let's start by rewriting the equation so all of the terms are on the left-hand side and then simplify as much as possible.

Now, we can identify the values of a, b, and c. x^2+3x-28=0 ⇕ 1x^2+ 3x+( - 28)=0 We see that a= 1, b= 3, and c= - 28. Let's substitute these values into the Quadratic Formula.

The solutions for this equation are x= - 3 ± 112. Let's separate them into the positive and negative cases.

Using the Quadratic Formula, we found that the solutions of the given equation are x_1=4 and x_2=- 7.