(a) Is the point (3, −5) on the line $5x + 3y + 6 = 0$? Justify your answer - Junior Cycle Mathematics - Question 5 - 2016
Question 5
(a) Is the point (3, −5) on the line $5x + 3y + 6 = 0$? Justify your answer.
(b) Find the point of intersection of the following two lines.
$3x + 2y = 7$
y = -2x ... show full transcript
Worked Solution & Example Answer:(a) Is the point (3, −5) on the line $5x + 3y + 6 = 0$? Justify your answer - Junior Cycle Mathematics - Question 5 - 2016
Step 1
Is the point (3, −5) on the line $5x + 3y + 6 = 0$?
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Answer
To determine if the point (3, −5) is on the line, we substitute x=3 and y=−5 into the equation of the line:
5(3)+3(−5)+6=0
Calculating this:
15−15+6=6
Since the left side equals 6, not 0, the point (3, −5) is not on the line. Therefore, the answer is no, it does not satisfy the line equation.
Step 2
Find the point of intersection of the following two lines: $3x + 2y = 7$ and $y = -2x + 5$
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Answer
To find the point of intersection, we will substitute the expression for y from the second equation into the first equation:
Substitute y:
3x+2(−2x+5)=7
Simplify:
3x−4x+10=7−x+10=7
Solve for x:
−x=7−10−x=−3x=3
Use the value of x to find y:
y=−2(3)+5=−6+5=−1
Thus, the point of intersection is (3,−1).
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