Question

How do you solve $7\left( {4x + 9} \right) - 13 = - 87$ ?

Answer 1

Hint: We can solve this problem by usual algebraic simplification. Also we know the BODMAS rule. This simplification is based on this rule.
First solve the bracket term and then multiply the bracket term by the term which is outside the bracket.
Finally, isolating all the terms that contain the target variable on one side of the equals and everything else on the other side and then manipulate as appropriate
Assume our target variable in this equation is $x$.

Complete step-by-step solution:
Given expression is, $7\left( {4x + 9} \right) - 13 = - 87$ ,
First of all we will have to expand the bracket and this is how we will get a normal solving equation and be able to find what $x$ is.
To expand the bracket using the BODMAS rule to solve the bracket.
To expand the bracket we have to know that we need to multiply everything inside the bracket by the outside.
Here we multiplied bracket term with $7$ we get,
$ \Rightarrow \left( {7 \times 4x + 7 \times 9} \right) - 13 = - 87$
The simplified the bracket term we get,
$ \Rightarrow 28x + 63 - 13 = - 87$ ,
Now reordering the right hand side term into the left hand side of equals, we get,
$ \Rightarrow 28x + 63 - 13 + 87 = 0$
Add and subtract the term we get,
$ \Rightarrow 28x + 137 = 0$
Taking the constant term $137$ into the right side of the equals because we need $x$ on its own we get,
$ \Rightarrow 28x = - 137$
Now our targeting variable is $x$ so we divide by how many $x$ we have to find what $1x$ is we get,
$ \Rightarrow x = \dfrac{{ - 137}}{{28}}$ or round it $x = - 4.8928$

Therefore the value of x is -4.8928.

Note: Here we have to discuss an equation of the type $ax + b = 0$ is called a linear equation in one unknown, where $a$ and $b$ are known numbers and $x$ is an unknown value. To solve this equation means to find the numerical value of $x$, at which this equation becomes an identity.