2x-5y=11,4x+10y=18 Use elimination
1 answer:
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Answer:
Number of students who scored atleast 1700 but less Than 2100 = 17
Step-by-step explanation:
Given the data :
1,450 1,620 1,800 1,740 1,650 1,800 2,010 1,780 1,840 1,490 1,620 1,480 2,390 1,640 1,830 1,710 1,900 1,910 1,950 1,820 1,590 2,350 2,260 1,870 1,530 1,950 2,000 1,830 1,980 2,100
Class interval __ Frequency
1400 - 1599 ____ 5
1600 - 1799 ____ 7
1800 - 1999 ____12
2000 - 2199 ___ 3
2200 - 2399 ___ 3
Number of students who scored atleast 1700 but less Than 2100 = 17
Part A.
The set of equations can be solved by substitution. Use the expression one equation gives for y as the value of y in the other equation. This gives
2x²-15 = 3x-6
Subtracting the right side gives a quadratic in standard form that can be solved by any of several methods.
2x² -3x -9 = 0
(2x+3)(x-3) = 0 . . . . factor the above equation
x = -3/2, x = 3 . . . . .use the zero product rule to find x
Now, these x-values can be substituted into either equation for y. The linear equation is often easier to evaluate.
y = 3(-3/2) -6 = -10.5
y = 3(3)-6 = 3
The solutions to the system are (-1.5, -10.5) and (3, 3).
Part B.
The two equations can be graphed. The solutions are where the graphs intersect. The graphs intersect where the (x, y) values that satisfy one equation are the same (x, y) values that satisfy the other equation. Those points of intersection are (-1.5, -10.5) and (3, 3).
The set of equations can be solved by substitution. Use the expression one equation gives for y as the value of y in the other equation. This gives
2x²-15 = 3x-6
Subtracting the right side gives a quadratic in standard form that can be solved by any of several methods.
2x² -3x -9 = 0
(2x+3)(x-3) = 0 . . . . factor the above equation
x = -3/2, x = 3 . . . . .use the zero product rule to find x
Now, these x-values can be substituted into either equation for y. The linear equation is often easier to evaluate.
y = 3(-3/2) -6 = -10.5
y = 3(3)-6 = 3
The solutions to the system are (-1.5, -10.5) and (3, 3).
Part B.
The two equations can be graphed. The solutions are where the graphs intersect. The graphs intersect where the (x, y) values that satisfy one equation are the same (x, y) values that satisfy the other equation. Those points of intersection are (-1.5, -10.5) and (3, 3).