15x+3x+10 = 38x-20x+10
18x+10 = 18x+10
18x-18x = 10-10
0 = 0
The equation is true.
The only error you made is on problem 3. Everything else is correct. Nice work.
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Here is how to solve problem 3
Plug x = 1 into the equation and solve for y
-3x + y = 1
-3*1 + y = 1 ... replace x with 1
-3 + y = 1
y - 3 = 1
y - 3 + 3 = 1 + 3 .... add 3 to both sides
y = 4
<h3>The answer is 4</h3>
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Verifying the answer:
Plug (x,y) = (1,4) into the equation. Both sides should be the same number after simplifying both sides.
-3x + y = 1
-3*1 + 4 = 1 ..... replace x with 1; replace y with 4
-3 + 4 = 1
1 = 1
The answer is confirmed.
If you were to graph -3x + y = 1, which is equivalent to y = 3x+1, you'll find that the point (1,4) is on this line.
Answer:
Step-by-step explanation:
-x+4y=16
-x=16-4y
x=(16/-1)-(4y/-1)
x=-16+4y
So average=(total of scores)/(number of tests)
needs at least average of 70
at least is represented as greater than or equal to or the sign (<u>></u>)
70<u>></u>(total)/(number oftests)
since we have 3 tests, we have to have 3 scores so
70<u>></u>(x+y+z)/3
he scored 85 and 60
70<u>></u>(x+85+60)/3 (doesn't matter which to subsitute)
70<u>></u>(x+145)/3
multiply obht sides by 3
210<u>></u>x+145
subtract 145 from both sides
65<u>></u>x
he needs to get at leas 65 on his third test
