<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
Using the law of cosines and sines, the measure of angle B is: 38.4°.
<h3>What is the Law of Cosines and Sines?</h3>
Law of cosines is: c = √[a² + b² ﹣ 2ab(cos C)]
Law of sines is: sin A/a = sin B/b = sin C/c
Use the law of cosines to find c:
c = √[12² + 18² ﹣ 2(12)(18)(cos 117)]
c ≈ 25.8
Use the law of sines to find angle B:
sin B/b = sin C/c
sin B/18 = sin 117/25.8
sin B = (sin 117 × 18)/25.8
sin B = 0.6216
B = sin^(-1)(0.6216)
B = 38.4°
Learn more about the law of cosines on:
brainly.com/question/23720007
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1 ) log ( 16 ) 4 = 1/2
Answer: B ) 1/2
2 ) 125 ^( 9 x - 2 ) = 150
9 x - 2 = log ( 125 ) 150
9 x - 2 = 1.038
9 x = 1.038 + 2
9 x = 3.038
x = 3.038 : 9
x = 0.3375
Answer: C ) 0.3375
3 ) log ( 3 x + 2 ) = 3
3 x + 2 = 10^3
3 x + 2 = 1000
3 x = 1000 - 2
3 x = 998
x = 998 / 3
Answer: B ) 998 / 3
