1. If the digits in 56 are interchanged, we get 65, Let us take the two digit number such that the digit in the units place is b. The di in the tens place differs from b by 3. Let us take it as b + 3. So the two-digit numb
Answers
Answer:
Some examples of expressions we have so far worked with are:
5x, 2x – 3, 3x + y, 2xy + 5, xyz + x + y + z, x
2
+ 1, y + y
2
Some examples of equations are: 5x = 25, 2x – 3 = 9,
5 37 2 , 6 10 2
2 2
y z + = + = −
You would remember that equations use the equality (=) sign; it is missing in expressions.
Of these given expressions, many have more than one variable. For example, 2xy + 5
has two variables. We however, restrict to expressions with only one variable when we
form equations. Moreover, the expressions we use to form equations are linear. This means
that the highest power of the variable appearing in the expression is 1.
These are linear expressions:
2x, 2x + 1, 3y – 7, 12 – 5z,
5
( – 4) 10
4
x +
These are not linear expressions:
x
2
+ 1, y + y
2
, 1 + z + z
2
+ z
3
(since highest power of variable > 1)
Here we will deal with equations with linear expressions in one variable only. Such
equations are known as linear equations in one variable. The simple equations which
you studied in the earlier classes were all of this type.
Let us briefly revise what we know:
(a) An algebraic equation is an equality
involving variables. It has an equality sign.
The expression on the left of the equality sign
is the Left Hand Side (LHS). The expression
on the right of the equality sign is the Right
Hand Side (RHS).
Linear Equations in
One Variable
CHAPTER
2
2x – 3 = 7
2x – 3 = LHS
7 = RHS
2