SOLUTIONS to business maths questions and answers PART 1.
1 (i). Solve 5x2 +9x - 2 = 0
Solution
Using general formula
x = -b± √b2 - 4ac
2a
Where a=5
b=9
c=-2
Substituting
= -9±√9²-4(5)(-2)
2(5)
= -9 ± √81+40
10
= −9±√121
10
= -9± 11
10
x = -9+11 or -9-11
10 10
X = 2 or -20
10 10
Therefore x = 0.2 or -2
, (ii)
Solve:
3x + 2y = 4y
5x - 4y = 26
SOLUTION
3x + 2y = 42... (i) x2
5x - 4y = 26... (ii) x1
6x + 4y =84
5x - 4y = 26
Adding equation (i) and (ii)
11x = 110
Divide both sides by 11
11x = 110
11 11
X = 10
To get y, substitute x = 10 into equation (i)
3x + 2y = 42... (i)
3(10) + 2y = 42
30 + 2y = 42
2y = 42 - 30
2y = 12
Divide both sides by 2
2y = 12
2 = 2
Y= 6
Therefore x = 10, y = 6
1 (i). Solve 5x2 +9x - 2 = 0
Solution
Using general formula
x = -b± √b2 - 4ac
2a
Where a=5
b=9
c=-2
Substituting
= -9±√9²-4(5)(-2)
2(5)
= -9 ± √81+40
10
= −9±√121
10
= -9± 11
10
x = -9+11 or -9-11
10 10
X = 2 or -20
10 10
Therefore x = 0.2 or -2
, (ii)
Solve:
3x + 2y = 4y
5x - 4y = 26
SOLUTION
3x + 2y = 42... (i) x2
5x - 4y = 26... (ii) x1
6x + 4y =84
5x - 4y = 26
Adding equation (i) and (ii)
11x = 110
Divide both sides by 11
11x = 110
11 11
X = 10
To get y, substitute x = 10 into equation (i)
3x + 2y = 42... (i)
3(10) + 2y = 42
30 + 2y = 42
2y = 42 - 30
2y = 12
Divide both sides by 2
2y = 12
2 = 2
Y= 6
Therefore x = 10, y = 6
