Algebra · real student question

For which value of x is 0.055x - 570 equal to (x - 78000)*0.055 + 1280?

Question

For which value of xx is

0.055x570=(x78000)0.055+1280?0.055x-570=(x-78000)\cdot 0.055+1280\,?

Step-by-step solution

  1. Expand the right-hand side into slope-intercept form. Distribute 0.0550.055 over the bracket:

    (x78000)0.055+1280=0.055x4290+1280=0.055x3010(x-78000)\cdot 0.055+1280=0.055x-4290+1280=0.055x-3010

    (the product 78000×0.055=429078000\times 0.055=4290 is exact).

  2. Set the two simplified expressions equal.

    0.055x570=0.055x30100.055x-570=0.055x-3010

  3. Cancel the xx-terms and read the result. Subtracting 0.055x0.055x from both sides leaves

    570=3010-570=-3010

    a statement with no xx in it that is simply false. When the variable vanishes and leaves a false numeric statement, the equation has no solution — as opposed to vanishing into a true statement such as 0=00=0, which would mean every xx works.

  4. Explain it structurally. Both sides are lines with the same slope 0.0550.055 but different intercepts 570-570 and 3010-3010. Parallel distinct lines never intersect, so there is no crossing point to find.

  5. Quantify the permanent gap. The difference is a constant, independent of xx:

    (0.055x570)(0.055x3010)=2440\left(0.055x-570\right)-\left(0.055x-3010\right)=2440

    Checked at x=0x=0: 570-570 versus 3010-3010, gap 24402440. At x=78000x=78000: 37203720 versus 12801280, gap 24402440. The first expression is permanently 24402440 larger, so equality is impossible.

Answer

No solution: the two expressions differ by the constant 2440 for every x\text{No solution: the two expressions differ by the constant } 2440 \text{ for every } x

Need to solve a different problem like this? Open the solver →