When you know the value for letters in an algebraic expression you can substitute these values into the expression and solve it.
Part ofMathsExpressions and equations
Sometimes you will have to substitute a number into an expression with a square number.
Remember when a number is squared it is multiplied by itself. This is straightforward when you have a positive value.
If \(x~=~10\)
Find \({x}^{2}~+~3\)
How to solve the expression:
\({x}^{2}~+~3\)
\(= {10}^{2}~+~3\)
\(= 10 \times 10~+~3\)
\(=~100~+~3\)
\(=~103\)
When you substitute a negative value for a square number you are multiplying a negative number by a negative number.
Remember that negative times negative equals positive, \(- \times -=+\).
If \(x~=~-10\)
\(= {-10}^{2}~+~3\)
\(= -10 \times -10~+~3\)
