Q. If 9x−10y=7 and −x−9y=6 are true equations, what would be the value of −10x+y ?Answer:
Equations to Solve: We have two equations:1) 9x−10y=72) −x−9y=6We need to find the value of −10x+y. To do this, we can solve the system of equations for x and y and then substitute these values into the expression −10x+y.
Isolate x: First, let's solve for x using the second equation. We can do this by isolating x on one side of the equation.−x−9y=6Multiply both sides by −1 to get x by itself:x=9y−6
Substitute x into 1st equation: Now that we have x in terms of y, we can substitute this expression for x into the first equation to solve for y. Substitute x=9y−6 into the first equation: 9(9y−6)−10y=7
Solve for y: Next, we expand the equation and simplify it to solve for y. 81y−54−10y=7Combine like terms:71y−54=7Add 54 to both sides:71y=61Divide both sides by 71:y=7161
Substitute y into x expression: Now that we have the value of y, we can substitute it back into the expression for x to find the value of x. x=9y−6 x=9(7161)−6
Calculate x value: We calculate the value of x by multiplying 9 by 61/71 and then subtracting 6. x=549/71−6 To subtract 6, we need to express it as a fraction with the same denominator as 549/71: x=549/71−426/71 x=(549−426)/71 x=123/71
Substitute x and y into expression: Finally, we substitute the values of x and y into the expression −10x+y to find the value we're looking for.−10x+y=−10(123/71)+(61/71)
Substitute x and y into expression: Finally, we substitute the values of x and y into the expression −10x+y to find the value we're looking for.−10x+y=−10(123/71)+(61/71) We calculate the value of −10x+y by multiplying −10 by 123/71 and then adding 61/71.y0Combine the fractions:y1y2
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