Answer:
Step-by-step explanation:
What he did at the end of the given equations is solve for x in x + 8y= 21
x = 21 - 8y Substitute that result in the top equation.
7(21 - 8y) + 5y = 14 is the correct step To continue Remove the brackets
147 - 56y + 5y = 14 Combine
147 - 51y = 14 Add 51y to both sides.
147 = 51y + 14 Subtract 14 from both sides.
133 = 51y divide by 51
y = 2.61 rounded.
The incorrect step is underlined and italicized.
