Algebra · real student question

Solve for x: 28 + 16x + 45 * 0.92 * (4 - 2x) + 350 * (4 - 2x) * 0.08 = 152.0621.

Question

Solve for xx:

28+16x+45(0.92)(42x)+350(42x)(0.08)=152.062128+16x+45(0.92)(4-2x)+350(4-2x)(0.08)=152.0621

Step-by-step solution

  1. Simplify the two numeric coefficients. Before touching the brackets, evaluate what multiplies each one:

    450.92=41.4,3500.08=2845\cdot 0.92=41.4,\qquad 350\cdot 0.08=28

  2. Combine the shared factor 42x4-2x. Both terms carry the same bracket, so they merge:

    41.4(42x)+28(42x)=(41.4+28)(42x)=69.4(42x)41.4(4-2x)+28(4-2x)=(41.4+28)(4-2x)=69.4(4-2x)

    Spotting the common factor first avoids expanding two separate products and halves the arithmetic.

  3. Expand and collect.

    28+16x+277.6138.8x=152.062128+16x+277.6-138.8x=152.0621

    305.6122.8x=152.0621305.6-122.8x=152.0621

    The xx coefficient is 16138.8=122.816-138.8=-122.8, so the left side decreases as xx grows.

  4. Solve for xx.

    122.8x=305.6152.0621=153.5379    x=153.5379122.81.25031122.8x=305.6-152.0621=153.5379\;\Longrightarrow\;x=\frac{153.5379}{122.8}\approx 1.25031

  5. Check by substitution. With x=1.2503086x=1.2503086: 42x=1.49938284-2x=1.4993828, so 69.4(1.4993828)=104.057269.4(1.4993828)=104.0572 and 16x=20.004916x=20.0049. Adding the leading 2828:

    28+20.0049+104.0572=152.0621  28+20.0049+104.0572=152.0621\;\checkmark

    Note the bracket 42x4-2x stays positive, which matters if it represents a remaining quantity in the underlying application.

Answer

x=153.5379122.81.2503x=\frac{153.5379}{122.8}\approx 1.2503

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