<u>Question 8</u>
a^2 + 7a + 12
= (a+3)(a+4)
When factorising a quadratic, the product of the two factors should equal the constant term (12), and the sum of the two factors should equal the linear term (7). To find the two factors, list out the factors of 12 (1x12, 2x6, 3x4) and identify the pair that adds up to 7 (3+4).
An alternative method if you get stuck during your exam would be to solve it algebraically using the quadratic formula and then write it in the factorised form.
a = (-7 +or- sqrt(7^2 - 4(1)(12)) / 2(1)
= (-7 +or- sqrt(1))/2
= -3 or -4
These factors are the negative of the values that would go in the brackets when written in factorised form, as when a = -3 the factor (a+3) would equal 0. (If it were positive 3 instead, then in the factorised form it would be a-3).
<u>Question 10</u>
-3(x - y)/9 + (4x - 7y)/2 - (x + y)/18
Rewrite each fraction with a common denominator so you can combine the fractions into one.
= -6(x - y)/18 + 9(4x - 7y)/18 - (x + y)/18
= (-6(x - y) + 9(4x - 7y) - (x + y)) /18
Expand the brackets and collect like terms.
= (-6x + 6y + 36x - 63y - x - y)/18
= (29x - 58y)/18
= 29/18 x - 29/9 y
2 + 2 = 4 5 + 5 = 10 + 4 = 14 your answer is 14
Step-by-step explanation:
Answer:
x = 8
Step-by-step explanation:
If the number 212x5 is a multiple of 3, the sum of the digits needs to be a multiple of 3, so we have:
2 + 1 + 2 + x + 5 = 10 + x
The value of x can be 2, 5 or 8
If the number is a multiple of 11, we have to calculate the first number minus the second, plus the third, minus the fourth... and so on, and the result needs to be a multiple of 11. So we have:
2 - 1 + 2 - x + 5 = 8 - x
x needs to be 8, so we have 8 - 8 = 0, that is a multiple of 11.
So the value of x is 8.
Answer:
x = 17deg
Step-by-step explanation:
Let angle y be the unknown angle IN THE TRIANGLE.
Angle y = 180 - 90 - 73
= 17deg
Angle x = Angle y (Alternate angles on 2 parallel lines)
Angle x = 17 deg
Answer:
40 cm.
Step-by-step explanation:
Given,
height of the object = 10 cm
Distance of the object from the X-ray= 50 cm
Distance of detector from the source = 2 m = 200 cm
Height of the image, h = ?
Now,
Again applying
h = 40 cm
Hence, height of the image is equal to 40 cm.
