# Graph Conditional Functions

Graph the following conditional functions:

(i) y = 5x + 7, -2 ≤x ≤2

(ii) y = -4x + 13, -1 ≤x ≤5

(iii) y = x² + 3x + 2, -4 ≤x ≤4

(iv) y = -2x² - 3x + 5, -1 ≤x ≤7

### Comments for Graph Conditional Functions

 Jul 26, 2012 Graph Conditional Functions by: Staff Part IThe answer: (i) y = 5x + 7, -2 ≤x ≤2 You can calculate an x-y table by hand, or use Microsoft excel to calculate values and to plot a conditional function.Calculation by hand:x       y = 5x + 7, -2 ≤x ≤2-5      NA (x is less than -2) -4      NA (x is less than -2) -3      NA (x is less than -2) -2      5*(-2) + 7 = -3-1      5*(-1) + 7 = 20      5*(0) + 7 = 71      5*(1) + 7 = 122      5*(2) + 7 = 173      NA (x greater than 2) 4      NA (x greater than 2) 5      NA (x greater than 2) The final table of values is:x       y -5 -4 -3 -2     -3-1       20        71      122      173 4 5 Calculation using Microsoft excel:For this function the first x cell value is: D10 (I used D10, but you can use whatever you want)Enter -5 into the D10 cell.The first y cell value is the following equation: E10 (I used E10, but you can use whatever you want)Enter =IF(AND(D10>=-2,D10<=2),5*D10+7,"")The second x cell value is: D11 Enter -4 into the D11 cell.The second y cell value is the following equation: E11 Enter =IF(AND(D11>=-2,D11<=2),5*D11+7,"")The third x cell value is: D12 Enter -3 into the D12 cell.The third y cell value is the following equation: E12 Enter =IF(AND(D12>=-2,D12<=2),5*D12+7,"")...and so on . . .The resulting table is exactly like the table computed by hand:-5 -4 -3 -2     -3-1       20        71      122      173 4 5 You can plot the computed values by hand, or use Microsoft excel to automatically plot the values-----------------------------------------------