Reflection across x axis and move 1 unit to the right
77(7) = 539, the total points of all her tests
539 - 18 + 81 = correct total points = 602
602/7 = 86 which is the new average
M + s = 10 or s = 10 - m
<span>3m + 2s = 23 </span>
<span>substitute first equation into second equation: </span>
<span>3m + 2(10 - m) = 23 </span>
<span>3m + 20 - 2m = 23 </span>
<span>m = 3 </span>
<span>using first equation: </span>
<span>s = 10 - 3 = 7 </span>
<span>check using second equation: </span>
<span>3(3) + 2(7) = 23 </span>
<span>9 + 14 = 23 checks </span>
<span>He hit 7 stationary and 3 moving targets.</span>
By substitution,
1.5x - 6 = -4.5x + 21
6x = 27
x = 4.5
Hence, y = 1.5(4.5) - 6 = 0.75
