Answer:
1/4(30+60+x) = x
Explanation:
x is the amount of time Hiroshi spends on his math homework. The total amount of time he spends on homework is given by the expression
30+60+x (30 minutes for history, 60 minutes for English and x minutes for math).
1/4 of this amount would be found by multiplying by 1/4:
1/4(30+60+x)
We're told that 1/4 of the total is the amount of time he spends on math. This means it equals x:
1/4(30+60+x) = x
To solve this, combine like terms in parentheses:
1/4(90+x) = x
Multiply both sides by 4 to cancel the fraction:
1/4(90+x)*4 = x*4
90+x = 4x
Subtract x from each side:
90+x-x = 4x-x
90 = 3x
Divide both sides by 3:
90/3 = 3x/3
30 = x
He spends 30 minutes on math homework.