Question

Simplify and find the value of \[4x+x-2{{x}^{2}}+x-1\] , when \[x=-1\] ?

Answer 1

Hint: In the given question, we have been asked to find the value of the given quadratic equation at x = -1. In order to order the question, first we will need to simplify the equation by combining the like terms. Then in this question, we are given an equation in terms of x and we need to solve this equation by putting the value of x i.e. \[x=-1\] which will satisfy the equation. For this we will perform certain operations i.e. addition, subtraction, multiplication, division on both sides of the equation such that we will get the value of the equation.

Complete step-by-step answer:
We have given the quadratic equation;
 \[\Rightarrow 4x+x-2{{x}^{2}}+x-1\]
Combining the like terms, we will get
 \[\Rightarrow -2{{x}^{2}}+6x-1\]
It is given in the question that \[x=-1\] .
Thus,
Substituting the value of \[x=-1\] in the above equation, we will get
 \[\Rightarrow -2{{\left( -1 \right)}^{2}}+6\left( -1 \right)-1\]
Simplifying the numbers in the above equation, we will get
 \[\Rightarrow -2-6-1=-9\]
Therefore,
The value of \[4x+x-2{{x}^{2}}+x-1\] at \[x=-1\] is equal to \[-9\] .
Hence, this is the required answer.
So, the correct answer is “-9”.

Note: While solving these types of questions, students just need to substitute the given value of variables in the equation and simplify the equation and they will get the required answer to the question. Students should always take care of the signs while solving the equation. Make sure to use proper operation i.e. addition, subtraction, multiplication, division on both sides of the equation such that we will get the value of the equation, as required.