2 Equations, formulae and inequalities

Front

PROCESS:

Substitute values into an algebraic formula

e.g. F = 2pq²

when p = 5 and q = -3

Back

Just replace the letters in the formula with the numbers you are given.

Watch out for minus signs!

e.g. F = 2pq²

=2 x (5) x (-3)²

= 2 x 5 x 9

= 90

Front

PROCESS:

Make something the subject of an algebraic equation

e.g. Make t the subject of the equation p = 3(t + 7)

Back

Front

PROCESS:

SOLVE an algebraic equation

e.g. 3x = 4(x -3)

Back

1. SAME STEPS AS REARRANGING

3. 1. Multiply by the bottom of any fractions to get rid of the fractions

4. 2. Expand brackets to get rid of those

5. 3. Add or subtract to get all the terms with x (or whatever is the new subject) on one side of the equals sign, and all the terms without x on the other side.

6. 4. If there is a number in front of the x, divide both sides by that.

e.g. 3x = 4(x - 3)

3x = 4x - 12

-x = -12

x = 12

Front

PROCESS:

Solve a quadratic equation

e.g. x² + 3x - 10 = 0

Back

1. 1. Factorise the quadratic.

2. 2. Take the numbers in the brackets and change the signs.

3. THERE ARE TWO SOLUTIONS

e.g. x² + 3x - 10 = 0

(x + 5)(x - 2) = 0

x = -5 or x = 2

Front

PROCESS:

Solve an inequality

e.g. 2x - 7 > 5

Back

Do just as you do for an equation, but with the < or > sign instead of =.

e.g. 2x - 7 > 5

2x > 12

x > 6