Variables and Algebraic Expressions: Applying the formula

$18x-7+4x-9-8x=\text{?}$

To solve the exercise, we will reorder the numbers using the substitution property.

$18x-8x+4x-7-9=$

To continue, let's remember an important rule:

1. It is impossible to add or subtract numbers with variables.

That is, we cannot subtract 7 from 8X, for example...

We solve according to the order of arithmetic operations, from left to right:

$18x-8x=10x$$10x+4x=14x$$-7-9=-16$Remember, these two numbers cannot be added or subtracted, so the result is:

$14x-16$

$14x-16$

$7.3\cdot4a+2.3+8a=\text{?}$

It is important to remember that when we have numbers and variables, it is impossible to add or subtract them from each other.

We group the elements:

$7.3×4a + 2.3 + 8a =$

29.2a + 2.3 + 8a = 

$37.2a + 2.3$

And in this exercise, this is the solution!

You can continue looking for the value of a.

But in this case, there is no need.

$37.2a+2.3$

$3x+4x+7+2=\text{?}$

$7x+9$

$3z+19z-4z=\text{?}$

$18z$

$7a+8b+4a+9b=\text{?}$

$11a+17b$

^{$13a+14b+17c-4a-2b-4b=\text{?}$}

$9a+8b+17c$

^{$a+b+bc+9a+10b+3c=\text{?}$}

_{^{$10a+11b+(b+3)c$}}

$5a+3a+8b+10b=\text{?}$

$8a+18b$

$35m+9n-48m+52n=?$

$61n-13m$

$8y+45-34y-45z=\text{?}$

^{$-26y+45-45z$}

^{$5.6x+7.9y+53xy+12.1x=\text{?}$}

_{^{$17.7x+53xy+7.9y$}}

^{$7.8+3.5a-80b-7.8b+3.9a=\text{?}$}

^{$7.8+7.4a-87.8b$}

$39.3:4a+5a+8.2+13z=\text{?}$

_{^{$13z+8.2+\frac{9.825}{a}+5a$}}

$3.4-3.4a+2.6b-7.5a=\text{?}$

^{$3.4-10.9a+2.6b$}

$\frac{1}{4}a+\frac{1}{3}x+\frac{2}{4}a+\frac{1}{8}+\frac{3}{8}=\text{?}$

$\frac{3}{4}a+\frac{1}{3}x+\frac{1}{2}$

$\frac{3}{8}a+\frac{14}{9}b+1\frac{1}{9}b+\frac{6}{8}a=\text{?}$

$1\frac{1}{8}a+2\frac{2}{3}b$