Answer: D
Step-by-step explanation:
Answer:
f(9)=-22-9(9)+20=-83
Step-by-step explanation:
f(9) means x = 9, Just substitute 9 into the function.
-9(9) = -81
-22-81+20 = -83
Answer: 3.6
Step-by-step explanation: 3x1.2= 3.6
Answer:
y - x = - 2 b
Step-by-step explanation:
Given-
3 x + 2 y = 5 a + b...................(i)
4 x - 3 y = a + 7 b.....................(ii)
<em><u>Multiply by 3 and 2 in equation (i) & (ii) respectively-</u></em>
<em><u>Add equation (iii) & (iv)-</u></em>
9 x + 6 y = 15 a + 3 a...................(iii)
<u>8 x - 6 y = 2 a + 14 b</u> ...................(iv)
17 x = 17 a + 17 b
<u>x = a + b</u>
Put x = a + b in equation (i)-
<em>2 y = 5 a + b - 3 a - 3 b</em>
<em>2 y = 2 a - 2 b</em>
<u>y = a - b </u>
<em>∴ y - x = a - b - ( a + b )</em>
<em>y - x = a - b - a - b</em>
y - x = - 2 b
