75.3k views
3 votes
How to solve this I don’t know how to solve it myself

How to solve this I don’t know how to solve it myself-example-1

1 Answer

2 votes

-4x^2-40x=-156

1. Write the equation in standard form:


\begin{gathered} \text{Add 156 in both sides of the equation:} \\ -4x^2-40x+156=-156+156 \\ \\ -4x^2-40x+156=0 \end{gathered}

2. Identify the coefficients a, b and c:


\begin{gathered} ax^2+bx+c=0 \\ \\ \text{For the given equation:} \\ a=-4 \\ b=-40 \\ c=156 \end{gathered}

3. Substitute the values into the quadratic equation:


x=\frac{-(-40)\pm\sqrt[]{(-40)^2-4(-4)(156)}}{2(-4)}

4. Solve the equation for x1 and x2:


\begin{gathered} x_{}=\frac{-(-40)\pm\sqrt[]{(-40)^2-4(-4)(156)}}{2(-4)} \\ \\ x_{}=\frac{40\pm\sqrt[]{1600+2496}}{-8} \\ \\ x=\frac{40\pm\sqrt[]{4096}}{-8} \\ \\ x=(40\pm64)/(-8) \\ \\ \\ x_1=(40-64)/(-8)=(-24)/(-8)=3 \\ \\ x_2=(40+64)/(-8)=(104)/(-8)=-13 \end{gathered}

Exact form and approximate form are the same for both solutions (x1 and x2):


\begin{gathered} x_1=3 \\ \\ x_2=-13 \end{gathered}

User Roman Svitukha
by
7.6k points

No related questions found

Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.

9.4m questions

12.2m answers

Categories