Hi I need help with questions 4-6 please

4. [14 Points] DETAILS WANEFMAC7 15.2.011.MI. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER 31" 31" 3f 61' Calculate , , , and when defined. (If an answer is undened, enter UNDEFINED.) 3X 31' 3X (1. -1) 3V (1. 1) fix, y) = (2x5: + 1)9 3r _ ' 8x 6r _ ' By 81" _ ax (1.4) 3 81" 7 3,, (1.4) 2 mm Help? 5. [11 Points] DETAILS WANEFMAC7 4.1.022. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER Use technology to obtain approximate solutions graphically. All solutions should be accurate to one decimal place. (Zoom in for improved accuracy.) 4x y=5 x+3y=11 (x.:(:l) Need Help? 6. [13 Points] DETAILS WANEFMAC7 1.3.088. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER The following table shows worldwide sales of a certain type of cell phone and their average selling prices in 2013 and 201?. n- Salaslmllllons) 1,030 2,030 (a) Use the data to obtain a linear demand function for this type of cell phone. Use your demand equation to predict sales to the nearest million phones if the price is raised to $375. :J million phones (b) Fill In the blank. For every $1 increase in price, sales of this type of cell phone decrease by :] million units