Answer:
<u>1</u><u>2</u>
2
Step-by-step explanation:
(3,7)(5,19)
(x,y)(x,y)
<u>y2</u><u>(</u><u>1</u><u>9</u><u>)</u><u>-</u><u> </u><u>y1</u><u>(</u><u>7</u><u>)</u>
x2(5)-x1 (3)
formula. <u>y2-y1</u>
x2-x1
30b + 100u = 900
5b + 25u = 200....multiply by -6
------------------
30b + 100u = 900
-30b - 150u = - 1200 (result of multiplying by -6)
------------------add
-50u = - 300
u = 6 <== upgrated phones sold
30b + 100u = 900
30b + 100(6) = 900
30b + 600 = 900
30b = 900 - 600
30b = 300
b = 10 <== basic phones sold
10(0.5x + 6) = 8
5x + 60 = 8
5x = 8 - 60
5x = -52
x = -52/5
x = -10.4
