Distribute terms inside parentheses: Distribute the 7 to both terms inside the parentheses.We need to apply the distributive property, which states that a(b+c)=ab+ac.So, 7(3y+4) becomes 7×3y+7×4.This simplifies to 21y+28.
Set up the equation: Set up the equation with the distributed terms.Now we have the equation 21y+28=21.
Subtract to isolate y: Subtract 28 from both sides of the equation to isolate the term with the variable y. We want to get y by itself on one side of the equation, so we need to remove the constant term from the left side. 21y+28−28=21−28. This simplifies to 21y=−7.
Divide to solve for y: Divide both sides of the equation by 21 to solve for y.To isolate y, we divide both sides by the coefficient of y, which is 21.2121y=21−7.This simplifies to y=−31.
More problems from Solve two-step equations with parentheses