Quadratic Equations

Question 0

Solve the equation:

(x - 7) (x - 11) = 0

Answer 0

X = 7
X = 11

Question 1

5x(sq) + 2x - 7

Answer 1

(5x + 7) (x - 1)

Question 2

(2x - 1) (4x + 3) = 0

Answer 2

X = 0.5
X = -0.75

Question 3

(5x - 7) (6x + 5) = 0

Answer 3

X = 7/5
X = -5/6

Question 4

Factorise and solve:

x(sq) - 10x - 24 = 0

Answer 4

(x + 2) (x - 12)
X = -2
X = 12

Question 5

If a quadratic equation doesnt factorise we use the …

Answer 5

Quadratic formula to solve it ( its given in the paper)

Another hint to use the formula is when it tells you to give the answer to (2dp)

Question 6

Solve:
X(sq) + 7x = 22
To get the numbers to insert into the formula

Answer 6

Re write as x(sq) + 7x - 22 = 0
A = 1
B = 7
C = -22

Question 7

Dean is designing a rectangular sign. The length of the sign must be 1.5m greater than its width. The plastic the sign is to be made from costs £9 per m2. Write a formula that Dean could use to work out the cost (c) of the plastic needed to make a sign of width (w in metres)

Answer 7

The width of the sign is w m so the length is (w + 1.5) m. The area of the sign is = l x w = (w + 1.5) x w = w(sq) + 1.5w. So the cost of the plastic is
c = 9(w(sq) + 1.5w) or
C = 9w(sq) + 13.5w