Question

How do you solve $40=5\left( x+9 \right)$ ?

Answer 1

Hint: We can see that the equation given in the question is a linear equation in one variable. We can bring the variable to one side and constant to another side. Then divide both LHS and RHS by the coefficient of x to find the unknown.

Complete step-by-step answer:
The equation given in the question is $40=5\left( x+9 \right)$ which is a linear equation
We can see that 5 and 40 have a common factor that is 5, we can divide both LHS and RHS by 5
$\Rightarrow 8=\left( x+9 \right)$
Let’s bring all constants to RHS and variable to LHS
We can subtract 9 from both LHS and RHS , so subtracting 9 both sides we get
$\Rightarrow -1=x$
So the solution to $40=5\left( x+9 \right)$ is equal to - 1

Note: In a system of linear equations to find out a unique solution the number of equations should not be less than the number of unknowns. We know that the given equation is a linear equation which has only one unknown variable, but if a linear equation has n unknown variables, then we will need at least an equation to find the value of all variables. We can solve this question by another method that is by graphical method we can draw the graph of y = x + 9 and y = 8 , and we can check the intersection point that will be our solution. In this case both the equations are of straight line so there will be one intersection point at x = -1 and y = 8.