Question

Malik's solution to the equation (2/5)x - 4y = 10, when x = 60, is shown below.

(2/5)x - 4y = 10

(2/5)x - 4(60) = 10

(2/5)x - 240 = 10

(2/5)x - 240 + 240 = 10 + 240

5/2((2/5)x) = 5/2(250)

x = 265

What error did Malik make first when solving the equation (2/5)x - 4y = 10.

Answer 1

Malik's first error was in the incorrect substitution of the value for 'x'. Instead of substituting (2/5)*60, Malik multiplied 4 by 60. The correct substitution leads to finding the value of 'y' to be 3.5.

Step-by-step explanation:

The first error Malik made when solving the equation (2/5)x - 4y = 10 was incorrectly substituting in the value for 'x'. When x = 60, Malik should have substituted 60 into the equation directly without changing the coefficient (2/5). Therefore, the correct substitution should have been (2/5)*60, not 4*60. The correct steps would be:

• (2/5)*60 - 4y = 10
• 24 - 4y = 10
• 4y = 24 - 10
• 4y = 14
• y = 14/4
• y = 3.5

Thus, the correct value for 'y' when x = 60 is 3.5, not 265.