There's something wrong with the first formula as brackets don't match.Originally Posted by Steves5a
8t+11 = 7t-6. You want to get aform of the equation with all the t's one one side and all the numbers on the other. You're allowed to do the same thing to each side (add or subtract the same thing, multiply or divide by the same thing). Subtract 7t from both sides. 8t+11-7t = 7t-6-7t. Group similar terms together. (8-7)t+11 = -6. Now subtract 11 from both sides. t+11-11 = -6-11. So t = -17.
You'll probably have been taught about 'taking things over to the other side'. That's a rule for knowing which of the possible things to do to each side. For example, if you see 7t on the right and want all the t's on the left you subtract 7t from both sides. The effect is to take +7t from the right and move it over to the left as a -7t. But what you're doing to each side is a subtraction.
Try the third: remember to group similar terms too.