Question

7. Multiply = 1/4x2Y2z,2/3xyz and - 6yz and verify the result for x = 2, y = 3,z=2​

Answer 1

Answer:

In earlier classes, we have already become familiar with what algebraic expressions (or simply expressions) are. Examples of expressions are:

x + 3, 2y – 5, 3x2, 4xy + 7 etc.

You can form many more expressions. As you know expressions are formed from variables and constants. The expression 2y – 5 is formed from the variable y and constants 2 and 5. The expression 4xy + 7 is formed from variables x and y and constants 4 and 7.

We know that, the value of y in the expression, 2y – 5, may be anything. It can be 2, 5, –3, 0,5/2 ,-7/3 etc.; actually countless different values.

The value of an expression changes with the value chosen for the variables it contains. Thus as y takes on different values, the value of 2y – 5 goes on changing. When y = 2, 2y – 5 = 2(2) – 5 = –1; when y = 0, 2y – 5 = 2 × 0 –5 = –5, etc. Find the value of the expression 2y – 5 for the other given values of y.

Number line and an expression:

Consider the expression x + 5. Let us say the variable x has a position X on the number line;

X may be anywhere on the number line, but it is definite that the value of x + 5 is given by a point P, 5 units to the right of X. Similarly, the value of x – 4 will be 4 units to the left of X and so on. What about the position of 4x and 4x + 5?

The position of 4x will be point C; the distance of C from the origin will be four times the distance of X from the origin. The position D of 4x + 5 will be 5 units to the right of C.